JP2626368B2 - Method for producing fiber reinforced thermoplastic resin sheet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a fiber-reinforced thermoplastic resin <br/> sheet.

[0002]

2. Description of the Related Art A method for producing a sheet-like material substantially free of bubbles by integrating a reinforcing fiber mat and a thermoplastic resin is disclosed in, for example, JP-B-63-15135 and JP-A-62-163.
-240514. By the way, although the form of the fiber mat used greatly affects the impregnation speed of the resin (sheet productivity), the strength of the impregnated sheet, the performance such as moldability, and the pressing force required during impregnation,
Very little has been specified so far. Slight exceptions are JP-B-1-53896 and JP-B-52-25.
No. 864 has a description. In the former publication, the space volume of the fiber mat is specified to be 40% by volume or less, and in the latter publication, when producing a fiber-reinforced thermoplastic foam, the compression force and the bulk density at that time are used. The form of the fiber mat is specified.

[0003]

In the fiber-reinforced thermoplastic resin sheet, the length of glass fiber used, the bunched state, the adhesiveness between the fiber and the resin, and the like are determined by the resin impregnation during sheet production and the sheet strength characteristics. In spite of having a great influence on the strength characteristics of the molded article after the sheet is molded,
Until now, there has been no clear definition of these. For this reason, the impregnation of the resin into the glass fiber is insufficient,
Or, due to poor adhesion between the resin and glass fibers, glass
The fiber reinforcing effect was not sufficiently exhibited.

On the other hand, the above-mentioned Japanese Patent Publication No. 1-53896 and Japanese Patent Publication No. 52-25864 attempt to define the form of glass fiber. Spatial volume of the fiber mat in KOKOKU 1-53896 Patent Publication No. provisions of 40 vol% or less
In the expression of the present invention, the space ratio e of the fiber mat corresponds to 0.6 or more. However, the porosity of the fiber mat (the ratio of the void volume in the mat) varies greatly depending on the pressure to be measured. That is, the porosity e decreases as the pressure increases. FIG. 2 shows an example in which the relationship between the pressing force and the void ratio of the glass fiber mat was measured. As shown in the figure, since the porosity of the fiber mat changes greatly depending on the pressing force of the mat, it has no practical meaning unless the measurement pressure is limited to the pressure applied to the material in the impregnation step. If the description of the above patent is interpreted as expressing the form of the fiber mat at zero pressing force, this case also has no substantial meaning. For example,
Even if the fiber mat has the same void ratio measured under a pressure of 0.5 kg / cm ² , the apparent void ratio e at zero pressure is obtained with and without needle punch.
In extreme cases, it can differ by a factor of three.

Next, in the case where the properties of the fiber mat are defined by the compressive force and the bulk density at that time in Japanese Patent Publication No. 52-25864, the bulk density is defined as the fiber in the present invention if the density of the fiber is limited. It can have the same meaning as the porosity of the mat. However, there is no mention of the composition ratio of the matrix and the fiber mat, that is, the relationship between the weight ratio or volume ratio and the form of the appropriate mat.

The present invention aims to provide a method capable of producing high yield of fiber-reinforced thermoplastic resin sheet in which the reinforcing effect is excellent to solve the above problems.

[0007]

Means for Solving the Problems The present inventors have conducted intensive studies to achieve the above object, and varied the composition ratio (volume ratio) of the matrix and the fiber mat and changed the form of the fiber mat. As a result of the investigation, it was found that there was a proper combination of the material constitution and the mat form, and further, the present invention was achieved by selecting a proper resin.

[0008] fiber-reinforced thermoplastic resin sheet thus be produced in the present invention, polyolefin-based resin containing an adhesive is applied polyolefin resin, length 6~100m
m and a glass fiber mat in which a partially opened glass fiber bundle is mixed.

[0009] Then, method for producing a fiber-reinforced thermoplastic resin sheet according to the present invention is a method for producing a thermoplastic resin sheet reinforced with glass fiber mat, when the volume ratio of matrix / glass fiber was A / B ( However, A + B
= 1), glass fibers having a porosity in the range of A to (AB) under the pressure applied in the matrix impregnation step, having a length of 6 to 100 mm, and partially opened. Using a glass fiber mat in which bundles are mixed, a polyolefin-based resin containing a polyolefin-based resin provided with adhesiveness as a matrix of the volume ratio is supplied to the mat, and then heated and pressed to apply the polyolefin-based resin to the mat. Then, the mat is cooled and solidified while applying pressure so that the mat does not swell in the thickness direction of the sheet.

[0010] The matrix and glass fibers which are constituents of the fiber reinforced thermoplastic resin sheet are selected according to the use of the sheet, required characteristics and the like.

The resin used as the matrix is selected from polyolefin resins such as polyethylene resin, polypropylene resin and polybutene resin.
As the polyolefin-based resin, a resin containing a polyolefin-based resin having an adhesive property is used. This resin is composed of a crystalline polyolefin (ordinary polyolefin) and an unsaturated carboxylic acid or an organic silane compound. It is obtained by reacting in the presence of a catalyst such as an oxide, and is a so-called modified polyolefin.

The glass fiber has a length of about 6 to 100 mm,
Preferably, an operation of opening a short fiber bundle of about 13 to 50 mm is performed to mix the partially opened glass fiber bundle, and the glass in which the partially opened glass fiber bundle is mixed. Used as a fiber mat. The percentage of partially opened glass fiber bundles in this glass fiber mat is 30%
It is preferable that this is the case.

The partially opened glass fiber bundle is in the following state. Figure 1
1 will be described. Figure 11 is a diagram schematically showing the state of the glass fiber bundles are glass fiber Taba及BiHiraku fiber, 2
0 indicates a gas fiber bundle, and 21 indicates a glass fiber. In this figure, (a) is a fiber bundle that has not been opened, and (b) is
(E) a diagram is opened fiber glass fiber bundles. These figures
The state of the opened glass fiber bundle as shown in (b)
Figure, (c), (d), and (e), the order of opening
Glass fibers that have been partially opened
The bundle is shown in the figures (b) and (c) among the above figures.
Refers to the state that That is, partially open
The glass fiber bundle that has been bound
The lath fiber bundle is partially peeled and several small bundles are connected.
Say something that is in a stale state. Also, small bundles are connected
Is a state in which a small bundle formed by peeling
Are glued together in place
A state in which the bundle is branched from the original glass fiber bundle. So
Then, the above-mentioned bundle of small bundles is simply the original glass
A state in which the fiber bundle is directly connected to one, and
And the original glass fiber bundle is split into several
Some of them are in a state of being left.

The aspect ratio of the glass fiber is 10
Desirably, it is not less than 00. The volume ratio of the matrix (A) / glass fiber (B) is determined from the strength and the like required for the product sheet, and is usually 0.95 / 0.05 to 0.60.
/0.40, preferably 0.9 / 0.1 to 0.7 /
It is set within a range of about 0.3.

The fiber mat has a space ratio of A to (A + B) under the pressure applied to the fiber mat in the matrix impregnation step in the matrix / fiber volume ratio (A / B, where A + B = 1). ) Are used. FIG. 1 shows the result of determining the relationship between the porosity and the matrix remaining outside the fiber mat without being impregnated. In the figure, □ indicates the case where the volume ratio of the fiber is 5% (accordingly, the volume ratio of the matrix is 95%), Δ indicates the case where the volume ratio of the fiber is 10%, ○ indicates 20%, Δ indicates 30%, and Δ Indicates the case of 40%. In the present invention, a fiber mat having a porosity in which the volume ratio of the matrix remaining outside the mat in FIG. 1 is 0 to 50% is used. Table 1 shows
Become like A preferable space ratio is a range where the volume ratio of the matrix remaining outside the mat is 0 to 46%, particularly 5 to 30%.

[0016]

[Table 1]

Since the actual mat is not always completely homogeneous, there may be a case where the average value of the space ratio e locally exceeds this value even if the average value is the same as the upper limit value. In such a case, the matrix which is not involved in the impregnation in the calculation is 5
About 90% by volume (e = 0.895 in the case of 90/10) may remain. If the fiber mat is homogeneous, e may be equal to the upper limit.

When performing the above-mentioned melt impregnation of the matrix,
The porosity e of the nonwoven fabric when pressure is applied is as follows:
You can ask. First, total weight W [g], area S
[Cm ^Two) And place a fiber non-woven fabric of any thickness
It is set on a pressurizing device with
At the same time, apply a predetermined pressure until the thickness of the non-woven fabric no longer changes.
(Usually about 5 minutes) to continue applying the same pressure. Next, compress
T (cm) and area S '[cm^Two] (Through
(Same as the normal initial area S) is measured. As a result, the space ratio e
Is obtained by the following equation.

[0019]

(Equation 1)

When the porosity e of the fiber mat hardly changes with temperature, the measurement may be performed at room temperature. However, when the fiber mat before impregnation includes a material other than reinforcing fibers, for example, a fibrous matrix, a powdery matrix, and an emulsion matrix, those excluding these components, that is, the voidage measurement, Only components that function as reinforcing fiber mats should be used for voidage measurements.
If the porosity of the fiber mat changes significantly with temperature, measure the porosity at a temperature equal to the temperature of the impregnation step.

Glass fiber mats having different porosity can be manufactured as follows. A discontinuous fiber bundle (chopped strand) of commercially available glass fiber is opened by applying a relatively weak shearing force to the fiber bundle using a device such as a Henschel mixer. At this time, the degree of fiber bundle opening can be changed by changing the stirring time in the mixer. That is, the fiber opening proceeds by stirring for a long time,
The bundle of bundled fibers has a low bulk density. In this way, the fiber aggregates having different bulk densities are dispersed in a mat shape using a fiber feeder or a condenser used in the nonwoven fabric industry, and the fiber mats having different bulk densities, that is, different void ratios, are obtained.
Is formed . Other methods for opening the fiber bundle include a method using a cylinder opener with a spike, a method for removing the fiber sizing agent with a solvent or the like, and a method for blowing high-speed air.

As a method for easily adjusting the porosity of the fiber mat, a large number of high porosity mats and low porosity mats whose porosity is known in advance are prepared in large quantities, and these two are laminated or mixed. By doing so, an arbitrary space ratio mat can be manufactured.

The fiber mat may be joined by a needle punch, or may be joined by a binder. Further, some or all of the fibers may be blended in one direction. Further, the structure may be non-uniform in the thickness direction, that is, a structure in which layers having different porosity are stacked, and as disclosed in JP-A-3-47740, the porosity is continuously changed in the thickness direction. A structure that changes may be used. In the case of a mat that is not uniform in the thickness direction, the entire porosity e can be used as a representative value. However, it is desirable from the viewpoint of the reinforcing effect that all the layers have the lower limit of the porosity of the invention or more. A fiber mat in which 30 to 95% of the fibers are unidirectionally oriented can be manufactured as follows.

A rotating drum-shaped cylinder having spikes on its surface in a state where the discontinuous fiber bundle cut to a length of 6 to 100 mm is left as it is or in a state where the fiber is opened to an arbitrary extent within a range where the fiber is not significantly damaged. Quantitatively.

The most typical method for opening a discontinuous fiber bundle is to use an apparatus called a spreader, a beater or a blender which is widely used as one of dry-type nonwoven fabric manufacturing apparatuses. As another method, a so-called Henschel mixer may be used. In addition, it is possible to open the fiber bundle to some extent only by air-feeding it with air through a cotton feeder having rotating blades or the like.

As a method of quantitatively supplying the discontinuous fiber bundle to the drum-shaped cylinder having a spike on the surface, a dry nonwoven fabric manufacturing technique can be applied as it is.

As a drum having a spike on its surface (spike drum), a drum mounted on a card machine widely used in the nonwoven fabric industry can be used as it is. In a carding machine, the fed fiber bundle is generally brought into contact with a rotating drum-shaped cylinder having spikes on its surface. The spikes arrange the fibers into a non-woven fabric just like a comb scoops hair. The fibers arranged on the rotating cylinder are ultimately transferred to a drum having other adjacent spikes, called a doffer, and transferred to the next step. The shape of the spike is generally a so-called metallic wire (saw blade shape) or a garment (needle shape).

The length protruding from the drum surface is several mm to
It is about 1 cm. The number of spikes to be planted is generally about tens to hundreds of points / inch ² . In the card machine, a rotating drum such as a takein, a walker, a stripper or the like can be provided in addition to the cylinder and the doffer in accordance with a target nonwoven fabric.

A nonwoven fabric in which some of the fibers are oriented in one direction can be formed by changing the rotation speed of a plurality of drums having spikes on the surface rotating adjacent to each other. The proportion of fibers oriented in one direction (the direction of rotation of the drum) depends on the type of fiber used, ie, the material,
It varies depending on the fiber length, fiber diameter, etc., the mixing state of the fibers and the degree of opening, the spike shape of the drum to be used, the number, the rotation speed, the fiber feed speed, and the like. In other words, if the fibers to be used and the apparatus are determined, the ratio of the fibers oriented in one direction can be controlled by controlling the feed speed of the fibers and the rotation speed of each drum. Therefore, by changing the feed speed and the number of rotations of each drum in advance for the fiber and the device to be used, the ratio of the fiber oriented in one direction in the nonwoven fabric formed for each condition is determined.
The operation may be performed based on this data. The minimum number of spike drums is two, and usually about 2 to 10, usually 2 to 5 spike drums. In general, the higher the rotational speed of the subsequent spike drum is, the higher the proportion of fibers oriented in one direction is, and the greater the number of spike drums connected in series is, the more the state becomes. Is done. Even if the number of rotations of the latter spike drum is not faster than that of the former spike drum, some of the fibers are oriented in the rotation direction. The method of measuring the percentage of fibers blended in one direction is generally measured directly by visual observation, but the other method is to quantify an enlarged photograph of the nonwoven fabric by computer image processing. Can also.

The porosity of the formed nonwoven fabric is influenced not only by the type and orientation of the fiber but also by the degree of fiber opening. In addition, the fiber opening progresses during the formation of the nonwoven fabric by passing through a spike drum or the like. However, if the fiber to be used and the device are determined, the porosity of the nonwoven fabric formed according to the feed speed of the fiber and the rotation speed of each drum becomes substantially constant. Then, it is sufficient to drive the vehicle based on this data.

The nonwoven fabric which can be produced by using a card machine is usually made of glass fiber and has a basis weight of several g / m ² to several tens g / m ² , and at most 100 g / m ² . Therefore, in order to produce a nonwoven fabric having an arbitrary basis weight, a method of arranging a plurality of card machines, stacking the nonwoven fabrics discharged from each card machine in multiple stages, and winding the nonwoven fabric produced by one card machine in a roll shape. After preparing a plurality of rolls, a method of laminating the nonwoven fabric while feeding out each roll, a combination of the above methods, and the like are considered. The laminate of the nonwoven fabric thus formed can be joined by mechanical means such as a needle punch to improve the strength of the nonwoven fabric. However, in these processes, the void ratio e of the processed nonwoven fabric is out of the range of the present invention. It is necessary to take care not to become Further, the nonwoven fabric laminate can be joined by a binder.

On the other hand, in the present invention, an oriented nonwoven fabric having an arbitrary basis weight can be obtained by a simplified process. The long nonwoven fabric taken out of one card machine is folded on a conveyor moving in parallel with the long direction, and the weight is set to an arbitrary weight so that the fiber orientation is not disturbed. The folding may be performed by providing a device for reciprocating the conveyor in a preceding stage in the traveling direction on the conveyor, and feeding out the long nonwoven fabric therefrom. What has a web feeding function, such as a conveyor and a reel, may be used for this apparatus. The folded laminated nonwoven fabric is made into a nonwoven fabric joined by processing such as needle punching. As a result, a nonwoven fabric having an arbitrary basis weight can be obtained without disturbing the fiber orientation in a single card machine with a minimum process and space.

The polyolefin resin may be in any form such as a film, a molten resin, a powder, a granule, and a fiber. Further, additives such as a heat stabilizer and a flame retardant may be added.

After the polyolefin-based resin is supplied, the mat is impregnated with the resin by heating and pressing until the polyolefin-based resin is at least softened and fluidized.
The heating temperature is at least a temperature at which the polyolefin-based resin can be softened, and varies depending on the type of the resin.

The impregnation pressure used in the present invention is 2 kgf / cm ² or less. In the case of continuously producing sheets, a method of performing impregnation and cooling between two endless belts is known (Japanese Patent Publication No. 63-15135). The low pressure may make the impregnating device inexpensive, and may increase the material yield without using a sealing material. However, since there is a possibility that the decrease in the sheet thickness may gradually progress with time, it is better to perform clearance control (lower limit control) on the pressed surface.

According to the method of the present invention, a fiber-reinforced thermoplastic resin foam can also be produced. In this case, after impregnation without bubbles, the pressure applied to the sheet is made lower than the pressure in the impregnation step, and the sheet is expanded in the thickness direction by the repulsive force of the fiber mat while heating to a temperature at which the resin can flow.

After the fiber mat is impregnated with the polyolefin resin, the mat may be cooled and solidified while applying pressure so that the mat does not expand in the sheet thickness direction.

[0038]

According to the method of the present invention, the porosity under the pressure applied during the impregnation of the fiber mat is such that when the resin is impregnated with the polyolefin resin as the matrix, the resin just fills the space of the fiber mat. 50% by volume of sheet
Which are not impregnated into the mat and remain in the range. The present inventors have found that when the porosity is equal to or less than the lower limit, the reinforcing effect of the fiber is significantly reduced. If the porosity is not more than the lower limit, when the pressure and temperature are applied to the material in the impregnation step, the remaining 50% by volume or more of the resin that does not impregnate the fiber mat will be removed in the sheet width direction before the impregnation is completed. Leaked to This phenomenon is more remarkable as the pressing force is higher, the resin clay is lower, and the pressing time is longer. As a result, in the impregnated sheet, the material yield (particularly resin) decreases in the width direction due to the outflow of the material, the fiber content increases due to the outflow of the resin, the thickness of the impregnated sheet decreases, and the like. Quality becomes unstable. In order to prevent this phenomenon, it is necessary to attach a sealing material having a predetermined thickness around the material in the impregnation step and the cooling step, but when using a fiber mat having a porosity adopted in the present invention, In this case, the outflow of the matrix is small even without this sealing material.

When a polyolefin-based resin containing a polyolefin-based resin provided with an adhesive property is used, the adhesiveness at the interface between the resin and the glass fiber is improved, and the tensile strength, bending strength, compression strength, and interlaminar shear strength are improved. The elasticity of tensile, bending and compression is also increased.

When a mat in which fiber bundles that are partially opened are mixed is used, the strength of the molded sheet is higher than that in the case of a fiber bundle that has only been sheared and has not been opened at all. When the fiber bundles that are partially opened have an appropriate mixing ratio, the fluidity of the fibers at the time of molding is also good, and the molding of a complex shape product having convex portions such as ribs can be performed. It can be carried out.

It is appropriate that the length of the glass fiber is about 6 to 100 mm, but outside of this range, undesirable phenomena occur. That is, when the length is less than 6 mm, the function of the reinforcing strength is insufficient, and the strength of the molded product is reduced. On the other hand, if the length exceeds 100 mm, the fluidity of the fibers during molding deteriorates, which makes the fibers unsuitable for molding complicated shaped articles.

[0042]

【Example】

(Example 1) Glass fiber bundle (manufactured by Fuji Fiberglass,
FES-13-1250, fiber length 13mm, fiber diameter 11μm, number of bundles
135) Henschel mixer FM75J made by Mitsui Miike Kakoki Co., Ltd.
It was charged by 1000g, and the mixture was stirred at Z _O S rpm the _O blade becomes circumferential beam approximately 40 m. The stirring time was changed to 10, 30, 60, and 120 seconds. When the glass fiber aggregate obtained after each stirring time was observed, it was observed that the fiber bundle opening progressed with an increase in the stirring time, and the fiber bundle gradually became bulky. The fibers after each stirring time were continuously fed by air to a cotton collecting device called a condenser manufactured by Chuo Cotton Machine Works to obtain four types of fiber mats having a width of 750 mm and a length of 1500 mm. The approximate mat of the fibers was fed to a device called a so-called random weber, and the fibers were dispersed and accumulated on a moving conveyor to obtain a target fiber mat. The basis weight of this fiber mat can be adjusted to about 994 g / m ² by adjusting the conveyor speed of the random weber.
And Next, the porosity e of each fiber mat is adjusted to a pressure of 1 kgf.
/ cm ² .

Thus, the basis weight is 994 g / m ² , and the porosity e at a pressure of 1 kgf / cm ² is 0.60, 0.67, 0.75, and 0.80, respectively, and the thicknesses with respect to this pressure are 1.0, 1.2, and 1.6, respectively.
, 2.0mm glass fiber mat (no needle punch)
I got For glass fiber mats with a space ratio of 30 cm x 30 cm, two of them and a polypropylene resin film containing polypropylene with a size of 30 cm x 30 cm, a film thickness of 0.78 mm, and an MI of 60 g / 10 minutes. (Nippon Petrochemical Co., Ltd., XJ2001B with Nisseki N-polymer P4
02 was kneaded at 10%), and four sheets were laminated in the order of polypropylene film / glass fiber mat / polypropylene film / polypropylene film / glass fiber mat / polypropylene film. This laminate has a matrix / fiber volume ratio of 0.80 / 0.20. This laminate is sandwiched between two 1 mm thick stainless steel plates,
It was heated and pressed at a pressure of 1 kgf / cm ² for 4 minutes with a hot press at ℃. Then, it was immediately moved to a cooling press at 25 ° C. together with the stainless steel plate, and was cooled and pressed at a pressure of 1 kgf / cm ² for 1 minute. No spacers or seals were used. As shown in FIG. 3, in the cross section of the obtained sheet, the matrix 3 was spread over almost the entire mat of the fibers 2 in the thickness direction except for the space ratio e = 0.60. Table 2 shows the evaluation results of this sheet. (Comparative Example 1) Space factor e of 1 kgf / cm ² of glass fiber mat
The sheet was produced in exactly the same manner as in Example 1 except that the values were 0.56 and 0.85. In this sheet, in the case of the space ratio e = 0.56, the outflow to the periphery of the polypropylene resin is increased, and as a result, the fiber content is lower than the set value.
It is higher than 20% by volume and the sheet thickness is 3.8 ~
It became thinner than 4.0mm. The cross section of the sheet 1 had a structure in which the matrix 3 and the fibers 2 were clearly laminated in layers as shown in FIG. In the case of the space ratio e = 0.85, the polypropylene resin could not fill the inside of the mat as shown in FIG. Table 2 shows the evaluation results of this sheet. (Comparative Example 2) A sheet was prepared under the same conditions as in Example 1, except that a normal film (XJ2001B, manufactured by Nippon Petrochemical Co., Ltd.) was used as the polypropylene film. The cross section of the obtained sheet was the same as that of FIG. Table 2 shows the evaluation results of this sheet.

Table 2 shows the relationship between the void ratio of the mat and the reinforcing effect,
In addition, the difference in strength due to the difference in the resin used (normal polypropylene use, polypropylene kneaded with polypropylene having adhesiveness) is shown by bending strength.

Table 2 shows the relationship between the porosity of the mat and the reinforcing effect. A comparison of the bending strength between Example 1 and Comparative Example 1 reveals that the porosity e of Comparative Example 1 is 0.56 (FIG. 4). And those with a space ratio e = 0.85 (FIG. 6)
= 0.60, 0.67, 0.75, 0.80 (Fig. 3), the strength was lower and the reinforcing effect was not sufficient. This is because the impregnation state of the resin was poor as described above.

Regarding the difference in the resin used, the strength of Comparative Example 2 using a normal polypropylene resin was lower than the strength of Example 1 using a polypropylene resin containing a polypropylene provided with adhesiveness.

Table 3 shows the difference in strength due to the difference in the resin used as described above. As shown in Table 3, the results of Example 1 using the polypropylene resin containing the polypropylene provided with the adhesive property were different from the results of Comparative Example 2 in terms of the tensile strength, the compressive strength, and the bending strength in addition to the bending strength. Good values were obtained for all of the strength evaluation items of the elastic modulus.

The resin sheets obtained in Example 1 and Comparative Example 2 shown in Table 3 were used as materials, and the required number of sheets was heated to about 210 ° C. in a far-infrared heating furnace. A beam 15 having the shape shown in FIG. 12 was formed by compression molding. This beam has a thickness of t4m
m, a width w ₁ each 20mm on either side of the flange portion, the width w ₂ of the upper surface 115 mm, height b of the side was 60 mm.
Then, attach this beam to an Amsler type testing machine,
A static bending test was performed. In this test, the shape of the pressing judge was a cylinder of 160R x 200 mm in width, the span of the jig for attaching the beam was 700 mm, and the crosshead speed was 20 mm.
/ Min. The results are shown in Table 4 and FIG. In FIG. 13, curve A is the result of Example 1, and curve B is the result of Comparative Example 2. According to Table 4 and FIG.
Can withstand a larger load than the beam of Comparative Example 2. That is, in the case of Comparative Example 2, bending fracture of the flange portion occurred with a smaller load than that in Example 1, whereas in the case of Example 1, even when a larger load was applied, the upper surface portion did not. It just buckled. Furthermore, the thing of Example 1 shows that it is suitable as a material of a product that requires a large amount of energy absorption, such as a bumper beam of an automobile, having a large displacement until breaking.

[0049]

[Table 2]

[0050]

[Table 3]

[0051]

[Table 4]

Example 2 The impregnation step and the cooling step
The operation was continuously performed between the endless belts. The clearance between the belts was 3.8 mm. The belt temperature was set to 200 ° C. in the impregnation step and 30 ° C. in the cooling step. No sealing material was used. The glass fiber mat uses the mat of Example 1 with 1 kgf / cm ² and the porosity e = 0.75, and the matrix uses the polypropylene film of Example 1
The composition ratio was matrix / fiber = 80/20% by volume.
The belt pressure was set at 1 kgf / cm ² . (Example 3) As a fiber mat, an inclined structure in which the porosity continuously changes in the thickness direction (Japanese Patent Laid-Open No. 3-47740),
Example 2 is the same as Example 2 except that the total space ratio e was 0.75 when measured at 1 kgf / cm ² . Example 4 A glass fiber bundle having a fiber length of 50 mm, a fiber diameter of 11 μm, and a bundle of 135 fibers (“FES-50-125”)
0 ", manufactured by Fuji Fiber Glass Co., Ltd.) (" Super Blender NDWG-20 "manufactured by Ikegami Kikai Co., Ltd.)
And the fiber bundle was pre-opened. This pre-opened glass fiber 5 is inserted into a card machine ("Card machine 60") as shown in FIG.
-M32 ", manufactured by Ikegami Kikai Co., Ltd.).
This card machine has a cylinder roll 6 having a diameter of 806 mmφ, a doffer roll 7 having a diameter of 522 mmφ, and 229 mm.
Has three spike rolls of Takein roll 8,
In addition, a 127 mm diameter walker roll and a 78 mm diameter
Each of the five stripper rolls (all not shown) is attached.

The supply amount of glass fiber was about 30 kg / hr, the removal rate of the nonwoven fabric from the doffer roll 7 was about 15 mpm, and a nonwoven fabric 9 having a basis weight of 22 g / m ² was obtained. After laminating 23 pieces of this glass fiber nonwoven fabric in the same fiber orientation direction, needle punching was performed at a pitch of 5 pieces / cm ² from above and below.

This glass fiber nonwoven fabric has a basis weight of about 500 g.
/ M ² , about 60% of fibers are unidirectionally oriented,
The porosity e at a pressure of 1.0 kgf / cm ² was 0.75. A predetermined number of 0.78 mm-thick films made of the same polypropylene resin having an MI of 60 g / 10 min and the same as that used in Example 1 were stacked on the four nonwoven fabrics from above and below, and pressed with a press heated to 200 ° C. at 1.0 kgf / cm. ^Two
Pressure of 5 minutes, then 1.0kgf / c with a normal temperature press
It was compressed at a pressure of m ² for 5 minutes to obtain a fiber-reinforced plastic resin sheet having a thickness of 4 mm and a glass fiber content of 19% by volume.

FIG. 8 shows a schematic diagram of a cross section of this sheet. The thermoplastic resin 3 sufficiently impregnated the nonwoven fabric of the glass fiber 2, and no air bubbles remained in the sheet.

Table 5 shows the mechanical strength in the orientation direction and the vertical direction of the sheet. (Comparative Example 3) A sheet was produced under the same conditions as in Example 4, except that a normal polypropylene film (XJ2001B, manufactured by Nippon Petrochemical Co., Ltd.) was used. Table 5 shows the mechanical strength in the orientation direction and the vertical direction of this sheet. (Comparative Example 4) 300 g of rovings aligned in one direction
m ² and random chopped strand mat 300g
/ M ² laminated glass fiber mat (“Lamimat LM303KA-104”, manufactured by Nitto Boseki Co., Ltd.) and a predetermined number of 150 μm-thick ordinary polypropylene film (Nippon Petrochemical Co., Ltd., XJ2001B). The roving direction was the same, and the layers were alternately laminated to obtain a sheet having a thickness of 4 mm and a glass fiber content of 40% by weight in the same manner as in Example 4. The porosity e of the glass fiber mat was 0.45 at a pressure of 1.0 kgf / cm ² , and the orientation component of the fiber was about 50%.

FIG. 10 shows a schematic diagram of a cross section of this sheet. The polypropylene resin 3 was not sufficiently impregnated in the glass fiber mat 13, and the resin and fiber layers were separated without being integrated. Table 5 shows the mechanical strength of this sheet.

According to Table 5, when the measurement results of Example 4 using a resin containing an adhesive polypropylene resin and Comparative Example 4 using a normal polypropylene resin are compared, Example 4 is clearer in each strength item. Is higher.

When the measurement results of Comparative Example 3 and Comparative Example 4 which use ordinary polypropylene resin are compared with each other, the resin sheet produced in Comparative Example 3 under the condition that the space ratio of the mat is small indicates that the resin The impregnation is not sufficient, and the flexural strength and flexural modulus at which the influence of the impregnation is particularly noticeable are inferior.

[0060]

[Table 5]

Using the resin sheets obtained in Example 4 and Comparative Example 4 as materials, the same beam as that described in FIG. 12 was produced as described above. Next, a destructive test was performed using the same tester and the same test method as described above. FIG. 13 shows the result. In FIG. 13, curve C is the result of Example 4 and curve D is the result of Comparative Example 4. As shown in this figure, the product of Example 4 required a large displacement before reaching the destruction and a large amount of energy absorption. Example 5 The fiber mat was subjected to needle punching 20 times per 1 cm ² to obtain a glass fiber mat having a mat space ratio of 0.78 at ² kgf / cm ² (fiber length 50 m).
m, fiber diameter 11 μm). Using this mat,
In the same manner as in Example 1, a sheet once impregnated was prepared. (The pressure at the time of impregnation is 2 kgf / cm ² ). Next, heating was continued at 200 ° C. in a state where the pressure was released without moving to the cooling step, and the sheet was expanded in the thickness direction by the repulsive force of the fiber mat. The foamed sheet obtained by cooling this is
The matrix was attached to almost the entire surface of the fiber, and it was a high-strength foam.

[0062]

Fiber-reinforced thermoplastic resin sheet thus be produced to the present invention, the polyolefin resin to be used has an adhesive property, a glass fiber mat is a reinforcement was partially dispersed fibers Since the bundles are mixed and the reinforcing effect is excellent, the strength is extremely large.

According to the production method of the present invention , the mat and the resin are used and the matrix is used.
Under the pressure applied during the resin impregnation process
Porosity based on the volume ratio of resin to glass fiber.
Sharpened fiber reinforced thermoplastic
In addition to providing a conductive resin sheet, the outflow of resin during impregnation is small, and the resin yield is high. Furthermore, the cost of the manufacturing equipment is low because it can be manufactured at low pressure.

[Brief description of the drawings]

FIG. 1 is a diagram showing the relationship between the fiber mat void ratio under impregnation pressure and the volume% of matrix remaining outside the mat after impregnation for each matrix / fiber volume.

FIG. 2 is a diagram showing a relationship between a pressing force and a void ratio of a fiber mat.

FIG. 3 is a cross-sectional view schematically showing an impregnated sheet obtained in an example.

FIG. 4 is a cross-sectional view schematically showing an impregnated sheet obtained in a comparative example.

FIG. 5 is a cross-sectional view schematically showing an impregnated sheet obtained in an example.

FIG. 6 is a cross-sectional view schematically showing an impregnated sheet obtained in a comparative example.

FIG. 7 is a side view schematically showing a fibrous nonwoven fabric manufacturing apparatus used in one embodiment of the present invention.

FIG. 8 is a schematic cross-sectional view of an example of a fiber-reinforced thermoplastic resin sheet according to an embodiment of the present invention.

FIG. 9 is a side view schematically showing a fibrous nonwoven fabric manufacturing apparatus used in one embodiment of the present invention.

FIG. 10 is a schematic cross-sectional view of a comparative example of a fiber-reinforced thermoplastic resin sheet.

FIG. 11 is a view schematically showing a state of a glass fiber bundle and a partially opened glass fiber bundle.

FIG. 12 is a perspective view showing a beam formed by using a resin sheet manufactured according to an example and a comparative example as a material.

FIG. 13 is a diagram showing a relationship between a load and a displacement of a beam formed using a resin sheet manufactured according to an example and a comparative example as a material.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fiber-reinforced thermoplastic resin sheet 2 Glass fiber 3 Polypropylene resin 13 Glass fiber mat 20 Glass fiber bundle 21 Glass fiber

Claims (1)

(57) [Claims] In the method for producing a thermoplastic resin sheet reinforced with a glass fiber mat, when the volume ratio of matrix / glass fiber is A / B (where A + B = 1),
The porosity under the pressure conditions applied in the matrix impregnation step is in the range of A to (AB), and the length is 6 to 1
A glass fiber mat in which a glass fiber bundle that is 00 mm and partially opened is mixed, and a polyolefin-based resin including a polyolefin-based resin provided with adhesiveness as a matrix of the volume ratio is supplied to the mat,
Then, the mat is impregnated with the polyolefin resin by heating and pressurizing, and then the mat is cooled and solidified while applying pressure so that the mat does not expand in the thickness direction of the sheet. Production method.