CN116803660A - Flow channel forming device and extrusion molding device - Google Patents
Flow channel forming device and extrusion molding device Download PDFInfo
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- CN116803660A CN116803660A CN202310251597.6A CN202310251597A CN116803660A CN 116803660 A CN116803660 A CN 116803660A CN 202310251597 A CN202310251597 A CN 202310251597A CN 116803660 A CN116803660 A CN 116803660A
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- flow path
- path forming
- flow channel
- surface roughness
- channel forming
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C44/00—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles
- B29C44/34—Auxiliary operations
- B29C44/36—Feeding the material to be shaped
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- Extrusion Moulding Of Plastics Or The Like (AREA)
Abstract
The present invention relates to a flow path forming apparatus and an extrusion molding apparatus. The purpose of the present invention is to provide a flow path forming device capable of producing a foam sheet with high foaming ratio and with which appearance defects caused by surface roughness are suppressed. The flow channel forming device of the present invention comprises at least a first flow channel forming member and a second flow channel forming member which form a tubular flow channel, wherein the plastic composition is formed by the flow channel formed by the first flow channel forming member and the second flow channel forming member, and the surface roughness parameter Rk of at least one of the flow channel forming surface of the first flow channel forming member and the flow channel forming surface of the second flow channel forming member is 1.0 [ mu ] m or more.
Description
Technical Field
The present invention relates to a flow path forming apparatus and an extrusion molding apparatus.
Background
Plastics are processed into a wide variety of article shapes for wide distribution. Foam sheets composed of a plastic composition have cushioning properties, and can be reduced in cost and weight by suppressing the amount of resin used, and therefore are widely used as materials for articles (resin molded articles) such as bags and containers. As a material of the foam sheet, for example, a thermoplastic resin such as a polystyrene resin, a polyolefin resin, a polyester resin, or the like is used.
In addition, in recent years, due to an increase in environmental awareness, development of materials in which a material of a foam sheet is replaced with a biodegradable plastic which is easily decomposed in nature has been actively conducted.
Among biodegradable plastics, polylactic acid has biodegradability and physical properties similar to those of polystyrene resins and the like conventionally used as plastics, and has a higher melting point, toughness, chemical resistance and the like than other biodegradable plastics, and from this point of view, it has been studied to use polylactic acid as a material of foam sheets.
Conventionally, there has been proposed a plug for use in a thermoplastic resin foam sheet production apparatus capable of producing a polypropylene resin foam sheet having a low expansion ratio and a low unit area weight, which has a reduced friction resistance and traction resistance due to shrinkage of a foam sheet, the thermoplastic resin foam sheet production apparatus comprising an extruder for melt-mixing a thermoplastic resin and a foaming agent and extruding the melt mixture, a die attached to a discharge port of the extruder, and a plug for producing a thermoplastic resin foam sheet by cooling a foam intermediate extruded from the die while traveling along an outer peripheral surface, wherein a fluororesin coating layer having an arithmetic average roughness Ra in a range of 0.5 μm to 4 μm is provided on an outer surface of the plug as a sheet contact surface (for example, refer to patent document 1).
[ patent literature ]
Japanese patent application laid-open No. 2005-246849 (patent document 1)
Disclosure of Invention
The purpose of the present invention is to provide a flow path forming device capable of producing a foam sheet with high foaming ratio and with which appearance defects caused by surface roughness are suppressed.
As means for solving the above problems, a flow channel forming device according to the present invention includes at least a first flow channel forming member and a second flow channel forming member that form a tubular flow channel, wherein a plastic composition is molded by passing through the flow channel formed by the first flow channel forming member and the second flow channel forming member, and a surface roughness parameter Rk of at least one of a flow channel forming surface of the first flow channel forming member and a flow channel forming surface of the second flow channel forming member is 1.0 μm or more.
The effects of the present invention are described below:
according to the present invention, a flow path forming apparatus capable of producing a foam sheet having a high expansion ratio and suppressing appearance defects caused by surface roughness can be provided.
Drawings
Fig. 1 is a schematic cross-sectional view showing an example of an embodiment of the present invention.
Fig. 2 is a schematic diagram showing an example of the continuous kneading apparatus.
Fig. 3 is a schematic view showing an example of the continuous foam sheet forming apparatus.
Fig. 4 is a phase diagram for defining a range of compressive fluids.
The symbols in the drawings are as follows:
1 first supply part
2 second supply part
3 compressive fluid supply unit
4 foam sheet
10 first flow passage forming member
20 second flow passage forming member
30 flow paths
40 flow channel forming surface
50 flow channel forming surface
100 continuous kneading device
110 continuous foam sheet forming device
Detailed Description
(flow passage Forming apparatus)
The flow channel forming device of the present invention includes a first flow channel forming member and a second flow channel forming member, and further includes other members as necessary.
At least one of the flow path forming surface of the first flow path forming member and the flow path forming surface of the second flow path forming member has a surface roughness parameter Rk of 1.0 μm or more.
In the prior art, the surface roughness Ra of the flow path of the molten resin is specified, but even if the surface roughness Ra is adjusted to produce a foam sheet, there is a problem that the foaming ratio is lowered and appearance defects are generated due to the corrugated wrinkles.
In the present invention, attention is paid to the fact that even in a production apparatus using any foaming agent, the start of foaming can be controlled freely, and the wrinkles in the form of waves can be effectively suppressed.
As a method for controlling foaming, pressure, temperature, time, atmosphere, blowing agent concentration, type, dispersibility, solubility control, filler concentration, filler dispersibility, molecular weight distribution of plastics, and the like are exemplified, and as a result, it has been found that when a flow channel forming apparatus having a surface roughness parameter Rk of 1.0 μm or more of the inner surface of the flow channel in the flow channel forming apparatus is used, a foam sheet having a reduced foaming ratio and reduced appearance defects such as surface roughness due to waviness wrinkles can be produced.
This is because the internal pressure of the flow path forming device can be maintained by increasing the flow resistance of the plastic composition before foaming, and thus, the abnormal foaming of the plastic composition can be suppressed. The Rk parameter represents the height of the portion of the cross-sectional shape as a whole excluding the extremely protruding mountain portions and the extremely protruding valley portions, and therefore, the gap represented by Rk is substantially the gap into which the plastic composition enters that can be used to increase friction. In addition, it is considered that the force of the gas from the foaming agent or the like in the gap floating the composition due to the entry and the friction reduction phenomenon caused by the gas occur simultaneously, and these effects are remarkably expressed in other surface roughness parameters represented by Ra (in particular, the protruding valley space volume (Vvv) specified in JISB0601:2001, the protruding valley depth (Rvk) specified in ISO25178, and the like), and therefore, it is necessary to subtract these latter parameters in order to increase the friction force, and it is particularly necessary that Rk is somewhat large.
The present invention will be described in detail below with reference to the embodiment shown in fig. 1. The present embodiment is not limited to the present invention.
In the example shown in fig. 1, the flow path forming device of the present invention includes a first flow path forming member 10, a second flow path forming member 20 opposed to the first flow path forming member 10, and a flow path 30 formed between the first flow path forming member 10 and the second flow path forming member 20.
By passing a plastic composition containing at least one plastic resin through the flow path 30, molding of the plastic composition can be performed.
The first flow path forming member 10 has a flow path forming surface 40 that forms the flow path 30, and the second flow path forming member 20 has a flow path forming surface 50 that forms the flow path 30.
The surface roughness parameter Rk as at least one of the flow path formation surface 40 and the flow path formation surface 50 is 1.0 μm or more, preferably 1.0 μm or more and 6.3 μm or less. When the surface roughness parameter Rk is 1.0 μm or more, a foam sheet having a high expansion ratio can be obtained.
The surface roughness parameter Rk is an index indicating the height of a portion excluding extremely protruding mountain portions and extremely protruding valley portions in the entire cross-sectional shape of the surface, and is a parameter based on JIS B0671-2:2002 standard.
The surface roughness parameter Rpk of at least one of the flow channel formation surface 40 and the flow channel formation surface 50 is preferably 0.45 μm or more and 6.4 μm or less. When the surface roughness parameter Rpk is 0.45 μm or more, no moire-like wrinkles are generated, and the maximum expansion ratio of the foam sheet can be improved. When the surface roughness parameter Rpk is 6.4 μm or less, roughness or bubble mark breakage is less likely to occur on the surface of the foam sheet.
The surface roughness parameter Rpk is an index indicating the height of a mountain extremely protruding from the cross-sectional shape of the surface, and is a parameter based on JIS B0671-2:2002 standard.
The surface roughness parameter RSm of at least one of the flow path formation surface 40 and the flow path formation surface 50 is preferably 55 μm or more and 200 μm or less. When the surface roughness parameter RSm is 55 μm or more, no moire-like wrinkles are generated, and the maximum expansion ratio of the foam sheet can be improved. When the surface roughness parameter RSm is 200 μm or less, roughness or bubble mark breakage is less likely to occur on the surface of the foam sheet.
The surface roughness parameter RSm is an index indicating the average length of a roughness curve element of the surface, and is a parameter based on JIS B0601:2013 standard.
The surface roughness parameter Rk is preferably 1.0 μm or more and 6.3 μm or less, and the surface roughness parameter Rpk is preferably 0.45 μm or more and 6.4 μm or less, as the flow path forming surface 40 and the flow path forming surface 50. Therefore, no corrugated wrinkles are generated, the maximum expansion ratio of the foam sheet can be increased, and the occurrence of roughness or foam breaking marks on the surface of the foam sheet can be prevented.
The surface roughness parameter Rk is preferably 1.0 μm or more and 6.3 μm or less, and the surface roughness parameter RSm is preferably 55 μm or more and 200 μm or less, as the flow passage forming surface 40 and the flow passage forming surface 50. Therefore, no corrugated wrinkles are generated, the maximum expansion ratio of the foam sheet can be increased, and the occurrence of roughness or foam breaking marks on the surface of the foam sheet can be prevented.
The surface roughness parameter Rpk is preferably 0.45 μm or more and 6.4 μm or less, and the surface roughness parameter RSm is preferably 55 μm or more and 200 μm or less, as the flow passage forming surface 40 and the flow passage forming surface 50. Therefore, no corrugated wrinkles are generated, the maximum expansion ratio of the foam sheet can be increased, and the occurrence of roughness or foam breaking marks on the surface of the foam sheet can be prevented.
The flow passage forming surface 40 and the flow passage forming surface 50 preferably have a surface roughness parameter Rk of 1.0 μm or more and 6.3 μm or less, a surface roughness parameter Rpk of 0.45 μm or more and 6.4 μm or less, and a surface roughness parameter RSm of 55 μm or more and 200 μm or less. Therefore, no corrugated wrinkles are generated, the maximum expansion ratio of the foam sheet can be increased, and the occurrence of roughness or foam breaking marks on the surface of the foam sheet can be prevented.
The surface roughness parameter Ra of at least one of the flow channel formation surface 40 and the flow channel formation surface 50 is preferably 0.8 μm or more and 6.3 μm or less. When the surface roughness parameter Ra is 0.8 μm or more, no moire-like wrinkles are generated, and the maximum expansion ratio of the foam sheet can be improved. When the surface roughness parameter Ra is 6.3 μm or less, roughness or foam breaking marks are less likely to occur on the surface of the foam sheet.
The surface roughness parameter Ra is an index indicating the surface roughness, and is a parameter based on JIS B0601:2013 standard.
The method for measuring the surface roughness parameter Rk, rpk, RSm, ra is not particularly limited, and may be measured using, for example, a portable roughness meter such as VK-X250 manufactured by KEYENCE corporation, SJ-210 manufactured by Mitsutoyo corporation, or the like. Specifically, the following measurement conditions were used to measure the product of KEYENCE, inc. by using VK-X250. In the case where the measurement conditions are based on the following, and there is a correlation of instrument errors, the correlation is not limited to this if it is grasped in advance.
[ measurement conditions ]
Measurement device, VK-X250 manufactured by KEYENCE Co
Brightness automatic setting
Double scan (automatic)
Measurement mode surface shape mode
Resolution 1024X 768
High precision mode
RPD, unset
Measurement of height spacing 0.1 μm
Single view field (no image combination)
Using X20 objective lens
[ image processing/detection ]
Plane correction "reference plane correction (entire area)".
Curved surface correction, surface shape waviness correction intensity 3"
Tie point removal
A total of 20 were measured with vertical lines (the average value at 20 was used for line roughness, and the parameters defining the surface roughness could be replaced by them).
Roughness detection, the end correction is performed without both cut-offs λs and λc.
The measurement field of view was about 536. Mu.m in the longitudinal direction, and about 714. Mu.m in the vertical direction.
The HRC hardness of at least one of the flow passage forming surface 40 and the flow passage forming surface 50 is preferably 28 or more. When the HRC hardness is 28 or more, a high foaming ratio is continuously obtained and appearance defects caused by surface roughness are continuously suppressed, and therefore, a device with low maintenance costs can be provided.
The HRC hardness can be measured by a method based on JISZ 2245.
Since the above-described HRC hardness measurement method is a failure test, the HRC hardness of the outermost surface may be referred to other hardness index or tensile test strength, or may be a sample inspection value of the material, as long as it can be confirmed in advance that the HRC hardness can be accurately estimated.
The contact angle of the flow passage forming surface 40 and the flow passage forming surface 50 with respect to water is not particularly limited, and may be appropriately selected according to the purpose, but is preferably 60 ° or more and 105 ° or less. When the contact angle is 60 ° or more, roughness or bubble mark breakage is less likely to occur on the surface of the foam sheet. When the contact angle is 105 ° or less, roughness or bubble mark breakage is less likely to occur on the surface of the foam sheet, and the pressure of the extruder is stable.
The method for measuring the contact angle is not particularly limited, and may be appropriately selected according to the purpose. For example, the measurement can be performed by the method according to JISR 3257.
The materials of the first channel forming member and the second channel forming member in the channel forming device are not particularly limited, and may be appropriately selected according to the purpose, and examples thereof include metals, steel, aluminum, plastics, stainless steel, pre-hard steel, cemented carbide, high-speed steel, that is, S45C, S50C, S C, A5052, SS400, SUS304, SUS316, SUS420, SKD11, SKH51, HPM-38, SCM415, SCM435, SCM440, and the like. In addition, they may have various coatings such as hard chrome plating treatment, electroless nickel plating treatment, aluminum oxide film treatment, black dyeing, park (Parker) treatment, carbide film formation, nitride film formation, oxide film formation, DLC treatment, silicone release treatment, fluorine release treatment, i.e., cr, ni, ni—p, amorphous alumina, crystallized alumina, zirconium, tiC, tiCN, tiN, WC, PTFE, ETFE, FEP, PCTFE, PFA, PVDF, or composite materials thereof, on which functional auxiliaries of plastics are compounded. Among them, hard chromium plating treatment is preferable. Therefore, no corrugated wrinkles are generated, the maximum expansion ratio of the foam sheet can be increased, and the occurrence of roughness or foam breaking marks on the surface of the foam sheet can be prevented.
The shape of the flow channel in the flow channel forming apparatus is not particularly limited, and may be appropriately selected according to the purpose, and examples thereof include a cylindrical shape, a polygonal prism shape, a horn shape, and the like.
The method of the flow channel forming device (hereinafter, sometimes referred to as "die") is not particularly limited, and may be appropriately selected according to the purpose, and examples thereof include a T-die, a flat die, a seamless die, and a round die. Among them, from the viewpoint of obtaining a sheet having a high expansion ratio and no waviness, a seamless mold is preferable, and a round mold is more preferable.
The size of the flow channel in the flow channel forming apparatus is not particularly limited, and may be appropriately selected according to the purpose, and the diameter of the tip of the discharge portion is preferably 70mm to 160mm, regardless of the shape of the flow channel. Thus, a sheet having a practical expansion ratio in the range of about 5 to 30 times can be easily produced without waviness, and the sheet width of the final product can be made to correspond to the sheet width required in the market, that is, 300mm or more and 1300mm or less.
The method for forming the flow channel forming surface in the flow channel forming apparatus is not particularly limited, and may be appropriately selected according to the purpose, and examples thereof include blasting and the like. Examples of the forming method include electrolytic, chemical etching, and machining by a lathe, in addition to the blasting.
As the blasting, in the case of using air, it is known to control roughness by controlling the work time, the blasting pressure, the distance from the work, the working angle, the shape of the medium, the material of the medium, and the like.
The blasting is affected by the environment such as the hardness of the outermost surface of the work, the structure of the construction equipment, the degree of deterioration of the medium, the nozzle shape, etc., but any roughness can be obtained by repeating trial production using test pieces or the like composed of the same raw materials as the product, for example, according to the relationship in which the surface roughness is increased by increasing the blasting pressure.
< Plastic composition >
The plastic composition contains at least one plastic resin, preferably a filler and a foaming agent, and may further contain other components as required. The plastic composition is a plastic composition obtained by foaming the plastic composition.
Plastic resin-
The plastic resin is not particularly limited and may be appropriately selected depending on the purpose, and for example, styrene-based homopolymers such as polystyrene and poly-p-methylstyrene, aliphatic polyester resins such as styrene-maleic anhydride copolymer, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-acrylonitrile-butadiene copolymer, styrene-acrylate copolymer, styrene-methacrylic acid copolymer, styrene-based resins such as a mixture of polystyrene and polyphenylene ether, polylactic acid, polyglycolic acid, poly (3-hydroxybutyrate), poly (3-hydroxybutyrate-co-3-hydroxycaproate), poly (3-hydroxybutyrate-co-3-hydroxyvalerate), polycaprolactone, polybutylene succinate, poly (butylene succinate-co-adipate) and the like may be used. One kind of them may be used alone, or two or more kinds may be used in combination. Among them, aliphatic polyester resins which are low-environmental-load polymer materials are preferable, and polylactic acid which is a carbon-neutralizing material and is relatively inexpensive is more preferable.
The aliphatic polyester resin may be synthesized from an alcohol component, a derivative thereof, and an acid component, a derivative thereof, or a commercial product.
Examples of the polylactic acid include a copolymer of D-lactic acid and L-lactic acid, a monomer of either D-lactic acid (D-form) or L-lactic acid (L-form), and a ring-opened polymer of at least one lactide selected from the group consisting of D-lactide (D-form), L-lactide (L-form) and DL-lactide. One kind of them may be used alone, or two or more kinds may be used in combination. The polylactic acid may be appropriately synthesized, or commercially available polylactic acid may be used.
The ratio of D-form to L-form of lactic acid constituting the polylactic acid is not particularly limited, but it is preferable that the ratio of D-form to L-form of polylactic acid is 95mol% or more in the polylactic acid. Polylactic acid composed of only one optical isomer of either D-form or L-form may also be used. The polylactic acid contained in the above range has high crystallinity, and a foam sheet produced using such polylactic acid can be expected to have heat resistance and is suitable for food applications and the like.
The content of the plastic resin is not particularly limited, and may be appropriately selected according to the purpose, and is preferably 90 mass% or more with respect to the total amount of the plastic composition.
The method for measuring the content of the plastic resin is not particularly limited, and may be appropriately selected according to the purpose, and for example, the weight ratio of the resin component may be measured by obtaining ash obtained according to JIS K7250-1.
Packing-
The filler (hereinafter, sometimes referred to as "foam core material") is contained for the purpose of adjusting the foaming state (size, number, arrangement, etc. of bubbles) of the plastic composition, reducing the cost, and improving the strength.
The filler is not particularly limited and may be appropriately selected according to the purpose, and examples thereof include inorganic fillers and organic fillers. One kind of them may be used alone, or two or more kinds may be used in combination.
Examples of the inorganic filler include talc, kaolin, calcium carbonate, layered silicate, zinc carbonate, wollastonite, silica, alumina, magnesium oxide, calcium silicate, sodium aluminate, calcium aluminate, sodium aluminosilicate, magnesium silicate, glass spheres, carbon black, zinc oxide, antimony trioxide, zeolite, hydrotalcite, metal fibers, metal whiskers, ceramic whiskers, potassium titanate, boron nitride, graphite, glass fibers, and carbon fibers. Among them, silica is preferable from the viewpoint of high affinity with a compressive fluid to be described later. In addition, when a filler other than silica is used as the base material, a filler surface-treated with silica is preferable.
Examples of the organic filler include naturally occurring polymers such as starch, cellulose fine particles, wood flour, bean dregs, rice hulls, and wheat bran, modified products thereof, sorbitol compounds, metal salts of benzoic acid and its compounds, metal salts of phosphate esters, and rosin compounds. Among them, cellulose is preferable from the viewpoint of low environmental load.
Foaming agent-
The blowing agent is not particularly limited and may be appropriately selected depending on the purpose, and examples thereof include hydrocarbons such as lower alkanes such as propane, n-butane, isobutane, n-pentane, isopentane, hexane, ethers such as dimethyl ether, halogenated hydrocarbons such as methyl chloride and ethyl chloride, and physical blowing agents such as compressed gases such as carbon dioxide and nitrogen. Among them, from the viewpoints of odorless gas, safe handling, and low environmental load, a compressible gas such as carbon dioxide or nitrogen is preferable.
By containing the above foaming agent, a plastic foam sheet with a high expansion ratio can be obtained.
Other ingredients-
The other components are not particularly limited and may be appropriately selected according to the purpose, and examples thereof include a crosslinking agent, a heat stabilizer, an antioxidant, and a plasticizer.
The crosslinking agent is not particularly limited and may be appropriately selected according to the purpose, but is preferably at least one selected from an epoxy compound and an isocyanate compound, for example, and more preferably an epoxy compound.
Foam sheets produced using an aliphatic polyester resin composition containing such a crosslinking agent can suppress the incorporation and breaking of bubbles and can improve the expansion ratio.
(foam sheet)
The foam sheet of the present invention is obtained by foaming the plastic composition of the present invention, and means a state obtained by foaming an aliphatic polyester resin composition.
The foaming ratio of the foam sheet is preferably 2 to 50 times, more preferably 5 to 40 times, and even more preferably 10 to 30 times. If the expansion ratio is less than 2 times, the strength is sufficient but the lightweight property is poor, and if the expansion ratio exceeds 50 times, the lightweight property is excellent but the strength is insufficient and the lightweight property is not suitable.
The method for measuring the expansion ratio of the foam sheet is not particularly limited, and may be appropriately selected according to the purpose, and for example, measurement may be performed by a buoyancy type specific gravity measuring device or the like. In addition, the bulk density and true density of the foam sheet can also be measured, and the expansion ratio calculated using the following formula:
Foaming ratio = true density [ g/cm ] 3 ]Bulk Density [ g/cm ] 3 ]
The foam sheet of the present invention is preferably substantially free of volatile components. The composition contains substantially no volatile component, and thus, the dimensional stability is improved, and in addition, the influence on the human body and the environment can be reduced. Examples of the volatile component include an organic solvent, a blowing agent such as butane, and the like.
In the present invention, as described later, for example, carbon dioxide (CO 2 ) And the like may also assume the function as a foaming agent. Therefore, when carbon dioxide or the like is used as the compressive fluid, the use of volatile components as the foaming agent can be avoided, and the foam sheet is easily brought into a state of substantially containing no volatile components. The term "substantially free" means that the detection limit is not higher than the detection limit by the following analysis.
A part of the foam sheet was used as a sample, 2 parts by mass of 2-propanol was added to 1 part by mass of the sample, and after dispersing by ultrasonic waves for 30 minutes, the foam sheet was stored in a refrigerator (5 ℃ C.) for 1 day or more, to obtain an extract of volatile components. The volatile component extract was analyzed by a gas chromatograph (GC-14A, manufactured by Shimadzu corporation) to quantify the volatile component in the foam sheet. The measurement conditions were as follows:
[ measurement conditions ]
Device Shimadzu GC-14A
Column CBP 20-M50-0.25
Detector-FID
The injection amount is 1 to 5. Mu.L
Carrier gas He2.5 kg/cm 2
Hydrogen flow rate 0.6kg/cm 2
Air flow rate 0.5kg/cm 2
Recording speed 5mm/min
Sensitivity Range101×Atten20
Column temperature of 40 DEG C
Injection temperature of 150 DEG C
That is, in the case of performing the following measurement, it is preferable that no organic compound having a boiling point of-20℃or more and less than 150℃at 1atm is detected in the foam sheet of the present invention.
[ measurement ]
A part of the foam sheet was dispersed in a solvent, and the volatile component extract was measured by a gas chromatograph under the above conditions to quantify the organic compound.
In order not to detect the organic compound when the above measurement is performed on the foam sheet, as described above, the foam sheet of the present invention may use CO 2 As the foaming agent, for example, a substance other than an organic compound such as a hydrocarbon may be used so that the content of the volatile component is substantially 0 mass%. By forming the foam sheet without detecting the organic compound, the foam sheet can be safely treated without generating odor or the like.
(extrusion molding apparatus and extrusion molding method)
The extrusion molding method includes an extrusion molding step, and other steps including a kneading step, a foaming step, and the like as necessary. The kneading step and the foaming step may be performed simultaneously or separately.
The extrusion molding method can be carried out by the extrusion molding apparatus of the present invention.
The extrusion molding apparatus includes a flow path forming apparatus and an extrusion molding means (mechanism), and may include other means as required.
Extrusion means (mechanism) and extrusion step
The extrusion molding step is a step of extruding the plastic composition through the flow channel of the flow channel forming device.
The extrusion step may be performed by the extrusion means.
Kneading device and kneading step
The kneading step is a step of kneading an aliphatic polyester resin and a crosslinking agent in the presence of a compressive fluid at a temperature lower than the melting point of the aliphatic polyester resin to obtain an aliphatic polyester resin composition.
The kneading process may be carried out by a kneading apparatus.
Since aliphatic polyester resins have a property of rapidly decreasing melt viscosity at or below the melting point, even if the additives are intended to be dispersed into the resin by kneading, the additives are liable to aggregate.
In addition, when the aliphatic polyester resin and the crosslinking agent are kneaded at a high temperature, the crosslinking reaction is accelerated, and the aliphatic polyester resin is polymerized, resulting in an increase in the gel fraction of the resin composition. By impregnating the compressive fluid, kneading can be performed in a high viscosity state at a temperature lower than the melting point, and the unreacted crosslinking agent can be dispersed in the aliphatic polyester resin. That is, the aliphatic polyester resin is kneaded in the presence of a compressive fluid, and then the crosslinking agent is added and kneaded to obtain a resin composition.
The present inventors have studied whether or not a compressive fluid can be effectively used in kneading an aliphatic polyester resin composition, particularly kneading polylactic acid and an additive, and as a result, have found that the viscosity of polylactic acid can be set to a viscosity suitable for kneading and the additive can be uniformly dispersed in the presence of the compressive fluid at a temperature lower than the melting point of polylactic acid. In contrast to kneading only in a region where the melt viscosity of polylactic acid is low at the time of kneading polylactic acid and additives, in the present invention, since kneading can be performed in a high-viscosity state at a temperature lower than the melting point of polylactic acid using a compressive fluid, the dispersibility of the crosslinking agent can be further improved.
Compressive fluid-
Examples of the substance that can be used in the state of the compressive fluid include carbon monoxide, carbon dioxide, nitrogen, nitrous oxide, methane, ethane, propane, 2, 3-dimethylbutane, ethylene, and dimethyl ether. Among them, carbon dioxide is preferable in view of its critical pressure of about 7.4MPa and critical temperature of about 31 ℃, and is easy to form a supercritical state, and is easy to handle due to incombustibility. These compressive fluids may be used alone or in combination of two or more.
Here, a compressive fluid used for producing the aliphatic polyester resin composition will be described with reference to fig. 4. Fig. 4 is a phase diagram for defining the range of compressive fluids. In the present embodiment, the term "compressive fluid" refers to a state in which a substance exists in any one of the regions (1), (2) and (3) shown in fig. 4.
In such a region, it is known that the substance is in a state of extremely high density and exhibits a behavior different from that at normal temperature and normal pressure. When a substance is present in the region of (1), the substance becomes a supercritical fluid. The supercritical fluid is a fluid which exists as a non-condensable high-density fluid in a temperature/pressure region exceeding a limit (critical point) at which gas and liquid can coexist, and which does not condense even when compressed. The liquid when the substance exists in the region of (2) is a liquefied gas obtained by compressing the substance in a gaseous state at normal temperature (25 ℃) and normal pressure (1 atm). The gas state when the substance exists in the region (3) means a high-pressure gas having a pressure of 1/2 (1/2 Pc) or more of the critical pressure (Pc).
The solubility of the compressive fluid varies depending on the combination of the type of resin and the compressive fluid, the temperature, and the pressure, and therefore, it is necessary to appropriately adjust the supply amount of the compressive fluid.
For example, in the case of a combination of polylactic acid and carbon dioxide, it is preferably 2% by mass or more and 30% by mass or less. If the carbon dioxide supply amount is 2 mass% or more, the disadvantage that the plasticizing effect is limited can be prevented. If the carbon dioxide content is 30 mass% or less, the carbon dioxide and polylactic acid are prevented from phase-separating, and the crosslinking agent is not sufficiently dispersed.
Kneading device
The kneading device used for producing the aliphatic polyester resin composition may be a continuous process or a batch process, but the reaction process is preferably selected appropriately in consideration of the device efficiency, product characteristics, quality, and the like.
As the kneading apparatus, a single screw extruder, a multi screw extruder, a kneader, a shaftless basket type stirring tank, BIVOLAK made by Sumitomo heavy industry Co., N-SCR made by Santui heavy industry Co., ltd., a tubular polymerization tank provided with spectacle blades, grille blades, kenix type, sulzer type SMLX static mixer made by Hitachi making Co., ltd., or the like can be used from the viewpoint of being able to cope with a viscosity suitable for kneading. From the viewpoint of color tone, finishers, N-SCR, twin-screw extruders, and the like, which are self-cleaning polymerization apparatuses, are exemplified. Among them, from the viewpoints of productivity, color tone of resin, stability, and heat resistance, finishers and N-SCR are preferable.
An example of the kneading apparatus is shown in FIG. 2. As the continuous kneading apparatus 100 of fig. 2, for example, a twin screw extruder (manufactured by JSW corporation) may be used. For example, screw diameter 42mm, l/d=48. In this example, raw materials such as polylactic acid and a crosslinking agent are supplied from the first supply unit 1 and the second supply unit 2 to the raw material mixing/melting region a, and mixed and melted. The mixed and melted raw material is supplied with the compressive fluid from the compressive fluid supply section 3 in the compressive fluid supply region b. Next, kneading is performed in the kneading section c. Next, in the compressive fluid removing region d, the compressive fluid is removed, and then, for example, the compressive fluid is formed into particles in the molding processing region e.
When the aliphatic polyester resin composition thus produced is used as a precursor in the production of a foam sheet, it may be referred to as a masterbatch. The aliphatic polyester resin composition subjected to processing such as granulation may also be referred to as a master batch.
The compressive fluid (liquid material) is supplied, for example, with a metering pump, and the solid raw material such as resin particles or crosslinking agent is supplied, for example, with a dosing machine.
Raw material mixing/melting zone a-
In the raw material mixing/melting region, the temperature of the resin particles is raised. In addition, if it is an additive (foam core) that does not react even at high temperature, it may be mixed with the resin. The heating temperature is set to be equal to or higher than the melting temperature of the resin, and the region where the compressive fluid is supplied is set to be uniformly mixed with the compressive fluid.
Compressive fluid supply region b-
When the resin particles are heated to be in a molten state, a compressive fluid is supplied to plasticize the molten resin.
Kneading zone c-
The kneading zone is set to a temperature to achieve a viscosity suitable for kneading the resin composition. The set temperature varies depending on the specification of the reaction apparatus, the type of the resin, the structure of the resin, the molecular weight, and the like, and thus is not particularly limited and may be appropriately changed. For example, in the case of commercially available polylactic acid having a weight average molecular weight Mw of about 200000, usual kneading is performed at a temperature of +10℃to 20℃of the melting point of the polylactic acid.
In contrast, in the present invention, it is characterized in that kneading is performed at a temperature lower than the melting point of polylactic acid, and kneading can be performed at a relatively high viscosity at a temperature lower than the melting point. The temperature is not particularly limited as long as it is lower than the melting point, but in order to suppress the crosslinking reaction of the crosslinking agent mixed in this region, it is preferable to proceed from the melting point of-30℃to-80 ℃.
Compressive fluid removal zone d-
In the compressive fluid removing region d, a pressure valve provided in the extruder is opened, and the compressive fluid is discharged to the outside.
Shaping process area e-
In the molding zone e, the aliphatic polyester resin composition is molded into an aliphatic polyester resin composition having an appropriate arbitrary shape such as pellets.
The pressure in each region in the extruder may be appropriately set, and for example, the pressure from the compressive fluid supply region b to the compressive fluid removal region d may be 7MPa.
< foaming Process >)
The foaming step is a step of foaming the aliphatic polyester resin composition when the compressive fluid is removed from the aliphatic polyester resin composition.
The foaming step is a step of foaming an aliphatic polyester composition (polylactic acid composition) by removing a compressive fluid.
The compressive fluid is gradually displaced from the air under the atmosphere and is removable from the foam sheet. For example, the compressive fluid is removed by opening the composition to the atmosphere. The temperature in the foaming step is preferably raised to a temperature near the melting point of the polylactic acid resin.
In the foaming step, the compressive fluid dissolved in the aliphatic polyester composition is subjected to an operation of reducing the solubility of the compressive fluid by pressure reduction, heating, or the like to supersaturate the compressive fluid, so that foam nuclei are mainly formed at the interface with the foam core material, and the compressive fluid dissolved in the aliphatic polyester composition diffuses into the foam nuclei, and the foam nuclei grow into bubbles, thereby obtaining a foam. Since foaming is performed starting from the foam core material, it is possible to produce a foam sheet having a uniform and fine foam after the foam core material is uniformly dispersed in polylactic acid. Even when the foam core is not used, a small amount of crystals generated in the kneading region substantially act as the foam core, and thus a foam sheet having a uniform and fine foam can be produced. However, if the crystallization is excessively performed, fluidity of the composition is lowered, and foaming itself may be difficult, so that it is preferable to add a foam core material.
< foam sheet Forming device >)
Next, a foam sheet was produced by a foam sheet producing apparatus. As the foam sheet forming apparatus, for example, an apparatus exemplified in the above-mentioned kneading apparatus can be used. The kneading device and the foam sheet forming device may be provided as one device or may be provided as different devices.
Fig. 3 shows an example of the foam sheet forming apparatus. The continuous foam sheeting apparatus 110 includes an extrusion apparatus 120. The extrusion molding apparatus 120 includes the flow channel forming apparatus 5 of the present invention and an extrusion molding mechanism (means) 6. As the extrusion molding mechanism (means) 6, a twin screw extruder can be used, for example, in the same manner as described above. In the continuous foam sheeting apparatus 110, for example, raw materials such as a master batch, a resin, and a foam core are supplied from the first supply unit 1 and the second supply unit 2 to the raw material mixing/melting area a, and mixed and melted. In the compressive fluid supply region b, the compressive fluid is supplied from the compressive fluid supply unit 3.
Next, kneading is performed in a kneading region c as a kneading means (mechanism) to obtain an aliphatic polyester composition. Further, the mixture is supplied to a heating zone d, heated and kneaded in the heating zone d, and thereafter, the mixture is opened to the atmosphere, for example, to be extruded and foamed. The extruded foam sheet 4 is wound along a mandrel.
In the continuous foam sheeting apparatus 110, the raw material mixing/melting zone a, the compressive fluid supply zone b, and the kneading zone c are also referred to as a first extruder, and the heating zone d is also referred to as a second extruder. In this example, the mixed, melted, kneaded raw materials were extruded from a first extruder to a second extruder, and extruded and foamed into a foam sheet by the second extruder. In the second extruder, for example, a round die may be used.
In this example, the kneading step is performed by a kneading device and a first extruder of a foam sheeting device, and the foaming step, which will be described later, is performed by a second extruder of the foam sheeting device. However, in the present invention, the structure is not limited to this. For example, the region where the kneading step and the foaming step are performed may be appropriately changed.
Raw material mixing/melting zone a-
In the raw material mixing/melting region, mixing and heating of the master batch, additives, resin particles, and the like are performed. When the concentration of the crosslinking agent contained in the master batch is high, the resin component is added and kneaded, whereby the concentration of the crosslinking agent is adjusted to an appropriate value. The type of the resin used is not particularly limited, and the above aliphatic polyester resin may be used. If the same resin as that in the master batch is used, the resin is uniformly mixed in the kneading step, and the unreacted crosslinking agent contained therein is also uniformly dispersed, which is preferable.
The additives that can be used are not particularly limited, and examples thereof include foam cores, heat stabilizers, antioxidants, plasticizers, and the like. The master batch may contain a crosslinking agent, but the crosslinking agent may be further added. The type of the crosslinking agent and the additive to be used is not particularly limited, and the above-mentioned materials and the like can be used as the crosslinking agent and the additive of the aliphatic polyester composition. One kind of them may be used alone, or two or more kinds may be used in combination.
By uniformly dispersing the foam core material in the resin in the kneading step, uniform and fine foaming can be expected. In addition, the foam sheet is used to improve crystallinity in addition to adjusting the bubble diameter, number density, and the like.
The crosslinking agent is necessary for achieving high expansion ratio and uniformity of the sheet by increasing the molecular weight of the resin. For the above reasons, in order to produce a foam sheet having a high expansion ratio and uniformity, the foam sheet preferably contains a foam core material and a crosslinking agent.
The timing of adding the above-mentioned additives is not limited. However, the timing of addition is not limited, and the foam core material may be added in the kneading step at the time of producing the aliphatic polyester composition, in the kneading step at the time of producing the foam sheet, or in both kneading steps, for example.
The amount of the crosslinking agent in the foam sheet varies depending on the molecular weight of the resin used or the molecular weight distribution of the resin. In particular, when a biodegradable resin is used as the aliphatic polyester resin, the content is preferably 3 mass% or less so as not to impair biodegradability.
The amount of the foam core material in the foam sheet is preferably 3 parts by mass or less. If it exceeds 3 parts by mass, the foam sheet may have hard and brittle physical properties. In particular, when a biodegradable resin is used as the aliphatic polyester resin, the content of the foam core material having no biodegradability is preferably smaller, and more preferably adjusted to 1 part by mass or less.
In the case of using a biodegradable resin as the aliphatic polyester resin, the total amount of the organic substances in the biodegradable resin to the foam sheet is preferably 98 mass% or more from the viewpoint of biodegradability and recyclability (ease of recycling). If the content is 98% by mass or more, the polylactic acid can be prevented from remaining, even if it is biodegradable, with other components not being biodegradable. If it is less than 98% by mass, good biodegradability cannot be obtained.
The organic substance in the foam sheet is mainly a biodegradable resin such as polylactic acid, and examples of the component other than polylactic acid include an organic core material and a crosslinking agent. When an inorganic core material is used as the foam core material, the inorganic core material does not correspond to the above-mentioned organic material.
Method for measuring content of polylactic acid
The content of polylactic acid can be calculated from the ratio of the materials to be added. If the material ratio is unknown, for example, the following GCMS analysis can be performed, and the components can be determined by comparing known polylactic acid with a standard sample. The area ratio of the spectrum obtained by NMR measurement or other analysis methods can be used for calculation as needed.
[ measurement of GCMS analysis ]
QP2010 manufactured by Shimadzu corporation, GCMS, with front Lab Py3030D as an auxiliary device.
Separation column, manufactured by front Lab, ultra Alloy UA5-30M-0.25F.
Sample heating temperature 300 DEG C
Column furnace temperature 50 ℃ (1 min hold) and heating to 320 ℃ (6 min hold) at 15 ℃/min.
Ionization method, electron ionization (E.I) method
The detection mass range is 25-700 (m/z)
In addition, the content of polylactic acid in the foam sheet may be analyzed by, for example, gas chromatography mass spectrometry (GC-MS), and a calibration line may be obtained in advance using known polylactic acid as a standard sample, whereby the ratio of polylactic acid in the foam sheet may be obtained. In this case, when the organic nuclei are identified by library search of the mass spectrum, the amount of the organic nuclei added may be quantified by creating a calibration line. The area ratio of the spectrum based on NMR measurement or other analysis methods may be combined as needed.
Compressive fluid supply region b-
Compressive fluid used in kneading step in foam sheet production
The same compressive fluid as described above can be used for the kneading step of the aliphatic polyester resin even in the kneading step in the production of the foam sheet. Among them, carbon dioxide has a critical pressure of about 7.4MPa and a critical temperature of about 31 ℃, and is easily brought into a supercritical state, and is easily treated with incombustibility, and the like, and is suitable from the viewpoint of such. These compressive fluids may be used singly or in combination of two or more.
In addition, the compressive fluid may also assume a function as a foaming agent according to the kind or the like. In general, a foaming agent is used in producing a foam sheet, but in the case of using a compressive fluid such as carbon dioxide or nitrogen as a foaming agent, kneading and foaming can be performed by a series of treatments, and thus, a production method is more preferable from the viewpoint of low environmental load.
The solubility of the compressive fluid varies depending on the combination of the type of resin and the compressive fluid, the temperature, and the pressure, and therefore, it is necessary to appropriately adjust the supply amount of the compressive fluid. For example, in the case of a combination of polylactic acid and carbon dioxide, the amount of carbon dioxide to be supplied is preferably 2 mass% or more and 30 mass% or less, when 100 parts by mass of the aliphatic polyester resin composition (polylactic acid and, if necessary, foam core material, crosslinking agent, etc.) is used. If the carbon dioxide supply amount is 2 mass% or more, the disadvantage that the plasticizing effect is limited can be prevented. If the carbon dioxide content is 30 mass% or less, the carbon dioxide and polylactic acid are prevented from phase separation, and a foam sheet having a uniform thickness cannot be obtained.
In addition, in the obtained foam sheet, if the volatile component is an organic solvent, a foaming agent such as butane, or the like, there is a possibility that the foam sheet may have an influence on the body or the environment. It is desirable that these volatile components are substantially absent. Since a compressive fluid such as carbon dioxide or nitrogen, which also has a function as a foaming agent, rapidly diffuses from the foam sheet to the atmosphere after the sheet is produced, the foam sheet is likely to be in a state substantially free of volatile components.
The term "substantially free" means that the detection limit is not higher than the detection limit by the following analysis.
2 parts by mass of 2-propanol was added to 1 part by mass of the aliphatic polyester resin composition to be measured, dispersed by ultrasonic waves for 30 minutes, and then stored in a refrigerator (5 ℃) for 1 day or more, whereby volatile components in the aliphatic polyester resin composition were extracted.
The supernatant of the stored dispersion was analyzed by a gas chromatograph (GC-14A, manufactured by Shimadzu corporation) to determine the volatile components in the aliphatic polyester resin composition. The measurement conditions were as follows:
[ measurement conditions ]
Device Shimadzu GC-14A
Column CBP 20-M50-0.25
Detector-FID
The injection amount is 1 to 5. Mu.L
Carrier gas He2.5 kg/cm 2
Hydrogen flow rate 0.6kg/cm 2
Air flow rate 0.5kg/cm 2
Recording speed 5mm/min
Sensitivity Range101×Atten20
Column temperature of 40 DEG C
Injection temperature of 150 DEG C
Other foaming Agents
Other foaming agents besides compressive fluids may be used. As described above, a compressive fluid such as carbon dioxide or nitrogen is preferable as the foaming agent, and as other foaming agents, physical foaming agents such as hydrocarbons such as lower alkanes such as propane, n-butane, isobutane, n-pentane, isopentane, hexane, ethers such as dimethyl ether, halogenated hydrocarbons such as methyl chloride and ethyl chloride, compressive gases such as carbon dioxide and nitrogen, and the like can be used in view of easiness in obtaining a foam sheet having a high expansion ratio.
< other procedures >
The other steps are not particularly limited, and examples thereof include steps performed in the production of a usual foam sheet. For example, a molding step of processing into a sheet may be mentioned.
Examples of the molding step include vacuum molding, pressure molding, and press molding. The sheet molded product is obtained by the above molding step. Further, a step of thermoforming a foam sheet to obtain a molded body, and the like can be exemplified.
< manufacturing article >)
The foam sheet of the present invention can be used as it is or as a product. The foam sheet of the present invention is excellent in light weight and heat resistance, and therefore is suitable as a container for food or tableware. The heat-resistant food container is suitable for use, but is not limited to such use. Further, the foam sheet of the present invention may be used as it is by printing or the like.
The product of the foam sheet of the present invention is not particularly limited, and may be appropriately modified. The article of the present invention comprises the foam sheet of the present invention, and optionally contains other components. The other components are not particularly limited as long as they are components used in a usual resin product, and may be appropriately selected according to the purpose.
The foam sheet of the present invention may also be processed into the article of manufacture of the present invention. The foam sheet may be processed using a mold to obtain a product, for example, without particular limitation. The method of processing the sheet using the mold is not particularly limited, and conventionally known methods of thermoplastic resins can be used, and examples thereof include vacuum molding, pressure molding, vacuum pressure molding, and press molding.
Examples of the product (which may be referred to as "consumer material") include packaging containers, trays, cutlery, and the like. The concept of the product includes not only a single product but also a component made of a product such as a handle provided with a tray, a product made of a product such as a tray to which a handle can be attached, and the like. The product may be a bag, stationery, or living goods.
Examples (example)
Hereinafter, examples of the present invention will be described, but the present invention is not limited to these examples.
Example 1
The S45C (manufactured by mis ii) was processed by a sand blaster (manufactured by Shan Tailang) using an alumina polishing medium for sand blasting at a processing angle of about 45 degrees to manufacture a first channel forming member and a second channel forming member in the channel forming apparatus. As shown in fig. 1, the first channel forming member 10 and the second channel forming member 20 form a channel 30, and an extrusion molding apparatus (continuous kneading apparatus) 120 as shown in fig. 3 is manufactured.
When the surface roughness parameters of the flow path formation surfaces of the first and second flow path formation members were measured, the surface roughness parameter Rk was 6.42 μm, the surface roughness parameter Rpk was 2.067 μm, the surface roughness parameter RSm was 139.9 μm, the surface roughness parameter Ra was 2.806 μm, and the contact angle was 74.2 °.
The polylactic acid and the filler were supplied so that the total flow rate thereof was 10kg/hr using an extrusion molding apparatus (continuous kneading apparatus) 120 shown in FIG. 3 equipped with a flow path forming apparatus 5. Polylactic acid A (4032D, melting point 168 ℃ C. Manufactured by Nature Works Co.) was supplied as polylactic acid at 9kg/hr, magnesite (MS-S, number average particle diameter 1.2 μm manufactured by Shendao chemical Co., ltd.) was supplied as filler at 1kg/hr, and carbon dioxide (corresponding to 10 mass% relative to polylactic acid) was supplied as a compressive fluid at 0.9kg/hr, and kneaded to obtain a polylactic acid composition and a sheet.
The temperature of each zone was set as follows:
190 ℃ in the raw material mixing/melting region a and the compressive fluid supply region b
Kneading zone c 160 DEG C
Heating area d is 160 ℃.
The pressure of each zone was set such that 10.0MPa was set from the compressive fluid supply zone b to the kneading zone c, 30MPa was set for the heating zone d, and 10MPa was set for the flow path forming apparatus 5. The sheet thickness was set to 3mm. The surface roughness parameters were measured by the following methods.
As a method for measuring the surface roughness parameters Rk, rpk, RSm and Ra, measurement was performed using a portable roughness meter such as VK-X250 manufactured by KEYENCE, SJ-210 manufactured by Mitsutoyo, or the like. Specifically, the following measurement conditions were used for measurement using VK-X250 manufactured by KEYENCE.
[ measurement conditions ]
Measurement device, VK-X250 manufactured by KEYENCE Co
Brightness automatic setting
Double scan (automatic)
Measurement mode surface shape mode
Resolution 1024X 768
High precision mode
RPD, unset
Measurement of height spacing 0.1 μm
Single view field (no image combination)
Using X20 objective lens
[ image processing/detection ]
Plane correction "reference plane correction (entire area)".
Curved surface correction, surface shape waviness correction intensity 3"
Tie point removal
A total of 20 were measured with vertical lines (the average value at 20 was used for line roughness, and the parameters defining the surface roughness could be replaced by them).
Roughness detection, the end correction is performed without both cut-offs λs and λc.
The measurement field of view was about 536. Mu.m in the longitudinal direction, and about 714. Mu.m in the vertical direction.
Example 2
In example 1, a polylactic acid composition and a sheet were obtained in the same manner as in example 1 except that the flow channel forming device 1 was changed to a flow channel forming device having a surface roughness parameter Rk of 1.2 μm, a surface roughness parameter Rpk of 0.419 μm, a surface roughness parameter RSm of 58.5 μm, a surface roughness parameter Ra of 0.794 μm, and a contact angle of 81.1 °. The surface roughness parameters were measured in the same manner as in example 1.
Example 3
A polylactic acid composition and a sheet were obtained in the same manner as in example 1 except that in example 1, the flow channel forming device 1 was changed to a flow channel forming device having a surface roughness parameter Rk of 3.5 μm, a surface roughness parameter Rpk of 3.332 μm, a surface roughness parameter RSm of 130.7 μm, a surface roughness parameter Ra of 1.904 μm, and a contact angle of 100 °. The surface roughness parameters were measured in the same manner as in example 1.
Example 4
In example 1, a polylactic acid composition and a sheet were obtained in the same manner as in example 1 except that the flow channel forming device 1 was changed to a flow channel forming device having a surface roughness parameter Rk of 1.26 μm, a surface roughness parameter Rpk of 0.486 μm, a surface roughness parameter RSm of 213.2 μm, a surface roughness parameter Ra of 1.23 μm, and a contact angle of 93.4 ° on the flow channel forming surfaces of the first and second flow channel forming members. The surface roughness parameters were measured in the same manner as in example 1.
Example 5
A polylactic acid composition and a sheet were obtained in the same manner as in example 1 except that in example 1, the flow channel forming device 1 was changed to a flow channel forming device having a surface roughness parameter Rk of 1.94 μm, a surface roughness parameter Rpk of 1.245 μm, a surface roughness parameter RSm of 34.9 μm, a surface roughness parameter Ra of 2.114 μm, and a contact angle of 107.4 ° on the flow channel forming surfaces of the first and second flow channel forming members. The surface roughness parameters were measured in the same manner as in example 1.
Example 6
A polylactic acid composition and a sheet were obtained in the same manner as in example 1 except that in example 1, the flow channel forming device 1 was changed to a flow channel forming device having a surface roughness parameter Rk of 5.99 μm, a surface roughness parameter Rpk of 2.753 μm, a surface roughness parameter RSm of 93.95 μm, a surface roughness parameter Ra of 2.776 μm, and a contact angle of 109.1 ° on the flow channel forming surfaces of the first and second flow channel forming members. The surface roughness parameters were measured in the same manner as in example 1.
Example 7
A polylactic acid composition and a sheet were obtained in the same manner as in example 1 except that in example 1, the flow channel forming device 1 was changed to a flow channel forming device having a surface roughness parameter Rk of 3.44 μm, a surface roughness parameter Rpk of 2.067 μm, a surface roughness parameter RSm of 58.69 μm, a surface roughness parameter Ra of 2.618 μm, and a contact angle of 87.99 ° on the flow channel forming surfaces of the first and second flow channel forming members. The surface roughness parameters were measured in the same manner as in example 1.
Example 8
In example 1, a polylactic acid composition and a sheet were obtained in the same manner as in example 1 except that the flow channel forming device 1 was changed to a flow channel forming device having a surface roughness parameter Rk of 12.5 μm, a surface roughness parameter Rpk of 7.645 μm, a surface roughness parameter RSm of 304.2 μm, a surface roughness parameter Ra of 6.45 μm, and a contact angle of 43.96 °. The surface roughness parameters were measured in the same manner as in example 1.
Example 9
In example 1, a polylactic acid composition and a sheet were obtained in the same manner as in example 1 except that the flow channel forming device 1 was changed to a flow channel forming device having a surface roughness parameter Rk of 2.9 μm, a surface roughness parameter Rpk of 0.882 μm, a surface roughness parameter RSm of 162.7 μm, a surface roughness parameter Ra of 2.347 μm, and a contact angle of 68.75 ° on the flow channel forming surfaces of the first and second flow channel forming members. The surface roughness parameters were measured in the same manner as in example 1.
Comparative example 1
In example 1, a polylactic acid composition and a sheet were obtained in the same manner as in example 1 except that the flow channel forming device 1 was changed to a flow channel forming device having a surface roughness parameter Rk of 0.88 μm, a surface roughness parameter Rpk of 0.48 μm, a surface roughness parameter RSm of 64.5 μm, a surface roughness parameter Ra of 0.978 μm, and a contact angle of 111.1 ° on the flow channel forming surfaces of the first and second flow channel forming members. The surface roughness parameters were measured in the same manner as in example 1.
Comparative example 2
In example 1, a polylactic acid composition and a sheet were obtained in the same manner as in example 1 except that the flow channel forming device 1 was changed to a flow channel forming device having a surface roughness parameter Rk of 0.38 μm, a surface roughness parameter Rpk of 0.177 μm, a surface roughness parameter RSm of 21.2 μm, a surface roughness parameter Ra of 0.712 μm, and a contact angle of 78.1 °. The surface roughness parameters were measured in the same manner as in example 1.
Comparative example 3
In example 1, a polylactic acid composition and a sheet were obtained in the same manner as in example 1 except that the flow channel forming device 1 was changed to a flow channel forming device having a surface roughness parameter Rk of 0.54 μm, a surface roughness parameter Rpk of 0.18 μm, a surface roughness parameter RSm of 40.8 μm, a surface roughness parameter Ra of 0.689 μm, and a contact angle of 48.3 ° on the flow channel forming surfaces of the first and second flow channel forming members. The surface roughness parameters were measured in the same manner as in example 1.
Comparative example 4
In example 1, a polylactic acid composition and a sheet were obtained in the same manner as in example 1 except that the flow channel forming device 1 was changed to a flow channel forming device having a surface roughness parameter Rk of 0.58 μm, a surface roughness parameter Rpk of 0.183 μm, a surface roughness parameter RSm of 47.5 μm, a surface roughness parameter Ra of 1.062 μm, and a contact angle of 114.2 ° on the flow channel forming surfaces of the first and second flow channel forming members. The surface roughness parameters were measured in the same manner as in example 1.
Comparative example 5
In example 1, a polylactic acid composition and a sheet were obtained in the same manner as in example 1 except that the flow channel forming device 1 was changed to a flow channel forming device having a surface roughness parameter Rk of 0.99 μm, a surface roughness parameter Rpk of 0.591 μm, a surface roughness parameter RSm of 30.7 μm, a surface roughness parameter Ra of 1.624 μm, and a contact angle of 58.8 °. The surface roughness parameters were measured in the same manner as in example 1.
Comparative example 6
In example 1, a polylactic acid composition and a sheet were obtained in the same manner as in example 1 except that the flow channel forming device 1 was changed to a flow channel forming device having a surface roughness parameter Rk of 0.95 μm, a surface roughness parameter Rpk of 0.545 μm, a surface roughness parameter RSm of 39.3 μm, a surface roughness parameter Ra of 1.083 μm, and a contact angle of 108.5 °. The surface roughness parameters were measured in the same manner as in example 1.
Comparative example 7
In example 1, a polylactic acid composition and a sheet were obtained in the same manner as in example 1 except that the flow channel forming device 1 was changed to a flow channel forming device having a surface roughness parameter Rk of 0.54 μm, a surface roughness parameter Rpk of 0.206 μm, a surface roughness parameter RSm of 24.7 μm, a surface roughness parameter Ra of 0.842 μm, and a contact angle of 55.6 °. The surface roughness parameters were measured in the same manner as in example 1.
Comparative example 8
In example 1, a polylactic acid composition and a sheet were obtained in the same manner as in example 1 except that the flow channel forming device 1 was changed to a flow channel forming device having a surface roughness parameter Rk of 0.07 μm, a surface roughness parameter Rpk of 0.02 μm, a surface roughness parameter RSm of 33.7 μm, a surface roughness parameter Ra of 0.52 μm, and a contact angle of 108.5 °. The surface roughness parameters were measured in the same manner as in example 1.
Comparative example 9
In example 1, a polylactic acid composition and a sheet were obtained in the same manner as in example 1 except that the flow channel forming device 1 was changed to a flow channel forming device having a surface roughness parameter Rk of 0.25 μm, a surface roughness parameter Rpk of 0.056 μm, a surface roughness parameter RSm of 75.86 μm, a surface roughness parameter Ra of 0.982 μm, and a contact angle of 68.83 ° on the flow channel forming surfaces of the first and second flow channel forming members. The surface roughness parameters were measured in the same manner as in example 1.
Next, for each of the obtained foam sheets, the expansion ratio and the appearance were evaluated as follows. The results are shown in Table 1.
< foaming Rate >)
The foaming ratio of the foam sheet was determined as follows.
Calculation of the expansion ratio
The foaming ratio of the foam sheet was determined by the following formula. The expansion ratio of the foam sheet was obtained by dividing the density (true density ρ0) of the composition constituting the foam sheet by the bulk density (ρ1) based on the following formula (1).
Expansion ratio=true density (ρ0)/bulk density (ρ1) formula (1)
The true density (. Rho.0) is the density of the plastic composition remaining as the final plastic composition, and the true density of polylactic acid is about 1.25g/cm 3 。
The bulk density was determined as follows: specifically, the foam sheet was allowed to stand in an environment adjusted to a temperature of 23℃and a relative humidity of 50% for 24 hours or more, and a test piece of 50 mm. Times.50 mm was cut. The volume density of the cut test piece was determined by an automatic densitometer (DSG-1, manufactured by Toyo Seisakusho Co., ltd.) using an in-liquid weighing method. This is a precise weighing of the foam sheet in the atmosphere (g), followed by a precise weighing of the foam sheet in water (g), calculated according to the following formula:
bulk Density [ g/cm ] 3 ]Sample weight in atmosphere [ g ]]/
{ (sample weight in atmosphere [ g ]]Weight in liquid [ g ]]X liquid Density [ g/cm ] 3 ]}
Based on the above formula (1), the foaming ratio is evaluated based on the obtained measurement values of the true density and the bulk density as follows.
[ evaluation criterion ]
The foaming ratio is 7.0 times or more
Wherein the foaming ratio is 5.0 times or more and less than 7.0 times
Delta is that the foaming multiplying power is more than 3.0 times and less than 5.0 times
X, the foaming multiplying power is less than 3.0 times
< appearance >
The appearance of the foam sheet was evaluated as follows.
The obtained foam sheet was visually observed, and appearance evaluation was performed based on the following criteria. The appearance evaluation was performed in a state where the foam sheet was observed in a range where no moire was generated and the foaming ratio was maximum.
[ evaluation criterion ]
Is that the surface of the foam sheet has no rough or bubble mark breaking trace
Rough or broken foam marks were visible on the surface of the foam sheet.
TABLE 1
The embodiments of the present invention have been described in detail above, but the present invention is not limited to the above embodiments, and various modifications may be made without departing from the gist of the present invention.
The present embodiment relates to the following modes:
＜1＞
a flow channel forming device comprising at least a first flow channel forming member and a second flow channel forming member forming a cylindrical flow channel, characterized in that:
forming the plastic composition through the flow path formed by the first flow path forming member and the second flow path forming member,
at least one of the flow path forming surface of the first flow path forming member and the flow path forming surface of the second flow path forming member has a surface roughness parameter Rk of 1.0 μm or more.
＜2＞
According to < 1 > the flow channel forming device, at least one of the flow channel forming surface of the first flow channel forming member and the flow channel forming surface of the second flow channel forming member has a surface roughness parameter Rk of 6.3 μm or less.
＜3＞
According to the flow channel forming device of < 1 > or < 2 >, the surface roughness parameter Rpk of at least one of the flow channel forming surface of the first flow channel forming member and the flow channel forming surface of the second flow channel forming member is 0.45 μm or more.
＜4＞
According to the flow channel forming device of < 1 > or < 2 >, the surface roughness parameter Rpk of at least one of the flow channel forming surface of the first flow channel forming member and the flow channel forming surface of the second flow channel forming member is 6.4 μm or less.
＜5＞
According to the flow channel forming device of < 1 > or < 2 >, the surface roughness parameter RSm of at least one of the flow channel forming surface of the first flow channel forming member and the flow channel forming surface of the second flow channel forming member is 55 μm or more.
＜6＞
According to the flow channel forming device of < 1 > or < 2 >, the surface roughness parameter RSm of at least one of the flow channel forming surface of the first flow channel forming member and the flow channel forming surface of the second flow channel forming member is 200 μm or less.
＜7＞
According to the flow channel forming device of < 1 > or < 2 >, the surface roughness parameter Ra of at least one of the flow channel forming surface of the first flow channel forming member and the flow channel forming surface of the second flow channel forming member is 0.8 μm or more and 6.3 μm or less.
＜8＞
According to the flow channel forming device of < 1 > or < 2 >, the contact angle of water with respect to at least one of the flow channel forming surface of the first flow channel forming member and the flow channel forming surface of the second flow channel forming member is 60 ° or more and 105 ° or less.
＜9＞
According to the flow channel forming device of < 1 > or < 2 >, at least one of the flow channel forming surface of the first flow channel forming member and the flow channel forming surface of the second flow channel forming member is hard chrome plated.
＜10＞
According to the flow channel forming device of < 1 > or < 2 >, the HRC hardness of at least one of the flow channel forming surface of the first flow channel forming member and the flow channel forming surface of the second flow channel forming member is 28 or more.
＜11＞
An extrusion molding apparatus, comprising:
the flow channel forming device according to any one of < 1 > - < 10 >, and
and an extrusion molding mechanism for passing the plastic composition through the flow path of the flow path forming device and extruding and molding the plastic.
＜12＞
The extrusion molding apparatus according to < 11 > comprising a kneading mechanism for kneading at least one plastic at a temperature lower than the melting point of the plastic and in the presence of a compressive fluid before extrusion molding by the extrusion molding mechanism.
＜13＞
According to < 11 > the extrusion molding apparatus, the plastic is a composition containing 90 mass% or more of polylactic acid.
The flow path forming device according to any one of the above items < 1 > - < 10 > and the extrusion molding device according to any one of the above items < 11 > - < 13 > can solve various conventional problems and achieve the object of the present invention.
Claims (13)
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2022-046328 | 2022-03-23 | ||
| JP2022190343A JP2023143671A (en) | 2022-03-23 | 2022-11-29 | Flow passage-forming apparatus, and extrusion molding apparatus |
| JP2022-190343 | 2022-11-29 |
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| Publication Number | Publication Date |
|---|---|
| CN116803660A true CN116803660A (en) | 2023-09-26 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202310251597.6A Pending CN116803660A (en) | 2022-03-23 | 2023-03-15 | Flow channel forming device and extrusion molding device |
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| Country | Link |
|---|---|
| CN (1) | CN116803660A (en) |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006224628A (en) * | 2005-02-21 | 2006-08-31 | Sekisui Plastics Co Ltd | Manufacturing method of polylactic acid resin foam sheet |
| US20180036934A1 (en) * | 2015-02-16 | 2018-02-08 | Yupo Corporation | Thermoplastic resin film and production method thereof, in-mold molding label, and plastic container with label and production method thereof |
| CN108215112A (en) * | 2016-12-09 | 2018-06-29 | 柯尼卡美能达株式会社 | Sizing die, extrusion forming device and the manufacturing method using their tubular part |
| CN110167738A (en) * | 2016-12-28 | 2019-08-23 | 坂东化学株式会社 | The manufacturing method of containers for food use |
-
2023
- 2023-03-15 CN CN202310251597.6A patent/CN116803660A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006224628A (en) * | 2005-02-21 | 2006-08-31 | Sekisui Plastics Co Ltd | Manufacturing method of polylactic acid resin foam sheet |
| US20180036934A1 (en) * | 2015-02-16 | 2018-02-08 | Yupo Corporation | Thermoplastic resin film and production method thereof, in-mold molding label, and plastic container with label and production method thereof |
| CN108215112A (en) * | 2016-12-09 | 2018-06-29 | 柯尼卡美能达株式会社 | Sizing die, extrusion forming device and the manufacturing method using their tubular part |
| CN110167738A (en) * | 2016-12-28 | 2019-08-23 | 坂东化学株式会社 | The manufacturing method of containers for food use |
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