WO2015184665A1 - Coating film having high water vapor transmission rate - Google Patents

Abstract

A coating film having a high water vapor transmission rate comprises: a basic film layer and a coating. The basic film layer is a bulk polytetrafluoroethylene film layer. The coating applied on the film layer is a polyurethane emulsion copolymer coating that contains hemp stem ultra-fine powder. A coating agent of the coating comprises raw materials of the following percentages by weight being evenly mixed: 20% to 25% of polyurethane, 55% to 60% of a dimethyl formamide solvent, 2% to 5% of a hydrophilic group solvent, and 18% to 25% of hemp stem ultra-fine powder. The resultant coating film has desirable moisture absorption performance and moisture guidance performance, has a high content of water vapor transmission factor cellulose of hemp stem ultra-fine powder and has micro trenches and micro pores, increases the moisture absorption area and the diffusion area, and has excellent performance of being anti-ultraviolet, water-proof, dust-proof, oil-proof, water vapor permeable, and corrosion resistant to oxidation solutions.

Description

 Large moisture permeability coating film

 The present invention relates to a large moisture permeable coating film. Background technique

 In the prior art, the bending venting of the automobile headlights of the European Union is defoamed to the condensation theory, and the sponge is dust-proof inside, and the air in the lamp can be greatly increased with the change of the temperature inside the lamp, thereby realizing the light faster. The inside of the fog is condensed, and the exhausted air of the curved pipe is used for a short time, and the dust and electrical components in the casing are rusted. Gore's theory of fog-to-condensation in the United States: The lamp is ventilated through the inside of the lamp and the outside of the lamp to establish a pressure balance. The water vapor in the lamp is discharged outside the lamp as the temperature inside the lamp rises. A larger gas permeable film patch method achieves fogging and de-condensation. Thereby, the phenomenon that the scattering of water by the water is blurred is unclear, and when the lamp is not working, the humid air of the external environment enters the casing. Nitto Denko's theory of fog-to-condensation: The headlights form air convection through the venting holes in the upper and lower positions of the lamp. The water vapor in the lamp is discharged from the venting hole in the upper position with the temperature inside the lamp. The venting holes constantly replenish the air outside the lamp. This reduces the ambiguity of the scattering of water by the water vapor. The theory uses a large number of venting plugs, which cannot solve the problem of condensation in the lower air temperature in the casing. Summary of the invention

The technical problem to be solved by the present invention is to provide a large moisture permeability coating film which has high water absorption, good moisture permeability and strong moisture discharge capability. In order to solve the above technical problem, one technical solution adopted by the present invention is: providing a large moisture permeability coating film, comprising: a base film layer and a coating layer, wherein the base film layer is an expanded poly 4 a fluoroethylene film layer, the coating layer coated on the expanded polytetrafluoroethylene film layer is a fine powder containing a hemp stalk core a polyamino phthalate emulsion copolymer coating; the coating agent of the polyamino phthalate emulsion copolymer coating containing the hemp stalk core ultrafine powder comprises the following weight percentages of raw materials: a polyamino hydrazine Acid ester 20%_25%; Dimercaptophthalamide solvent 55%_60%; Hydrophilic group solvent 2%-5%; Hemp stalk core ultrafine powder 18%-25%.

 O. 025mm - 0. 025mm。 The thickness of the polyacrylic acid ester emulsion coating having a thickness of 0. 012mm - 0. 025mm. In a preferred embodiment of the invention, the coating agent has a viscosity index of 33 Pa.s. In a preferred embodiment of the invention, the coating agent comprises from 35% to 45% of non-volatiles. In a preferred embodiment of the present invention, the manufacturing process of the hemp stalk core ultrafine powder comprises: first processing the hemp stalk core into a coarse powder, and performing pretreatment, followed by refining treatment and activation treatment, After the treatment is completed, the drying is carried out, and then the modification treatment is carried out, and then the micronization treatment is carried out, and finally the separation treatment is carried out to obtain the ultrafine fine powder of the hemp stalk core.

In a preferred embodiment of the present invention, the modification treatment is a polymerization modification of diphenyl decane diisocyanate and a polyol in a hemp stalk core after pulverization and drying. In a preferred embodiment of the present invention, the preparation process of the large moisture permeability coating film comprises the following steps: a) feeding the coating agent and adjusting the thickness of the coating; b) unwinding the expanded polytetrafluoroethylene a film layer, and a coating agent is contacted with the coating agent to form a polyaminophthalate emulsion copolymer coating containing an ultrafine powder of hemp stalk core on the surface of the expanded polytetrafluoroethylene film layer; c) containing a hemp stalk core Ultrafine powder polyamino phthalate emulsion copolymer coating for heating and drying; d) aging solidification, that is, a large moisture permeability coating film is obtained. 012毫米- 0. 025mm。 In a preferred embodiment of the present invention, the thickness of the glue is 0. 012mm- 0. 025mm. In a preferred embodiment of the invention, in step c), the heating and drying temperature is from 80 ° C to 100 ° C. In a preferred embodiment of the invention, in step d), the curing is carried out for at least 24 hours in an environment at a temperature of 20 ° C -4 {TC. The invention has the beneficial effects that: the large moisture permeability coating film of the invention has good moisture absorption and moisture permeability performance, and the moisture permeability factor cellulose containing the ultrafine powder of the hemp stalk core has a large content, and has a large amount of hydroxyl groups and water molecules. There are many bonding groups, and there are micro-grooves and micropores at the same time, which increase the moisture absorption area and diffusion area. It has excellent UV resistance and fully meets the requirements of automobile lamps and other small precision electronic devices (mobile phones, navigation terminals, miniatures). Computers, etc.) Reliable performance, comprehensive protection requirements in waterproof, dustproof, oil proof, moisture permeable, anti-oxidation solution corrosion. DRAWINGS

 In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly described. It is obvious that the drawings in the following description are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained according to the drawings without any creative work, wherein: FIG. 1 is a preferred embodiment of the large moisture permeability coating film of the present invention. Schematic diagram of the structure; the components of the drawings are marked as follows: 1. Expanded polytetrafluoroethylene film layer, 2. Polyaminophthalate emulsion copolymer coating containing ultrafine fine powder of hemp stalk core. detailed description

The technical solutions in the embodiments of the present invention will be clearly and completely described below. It is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all of those obtained by those of ordinary skill in the art without creative efforts The embodiments thereof are all within the scope of protection of the present invention.

 Referring to FIG. 1 , an embodiment of the present invention includes:

 A large moisture permeability coating film comprising: a base film layer and a coating layer, wherein the base film layer is an expanded polytetrafluoroethylene film layer 1 coated on the expanded polytetrafluoroethylene film layer 1 The coating is a polyamino phthalate emulsion copolymer coating 2 containing a hemp stalk core ultrafine powder.

 Example 1

 The coating agent of the polyamino phthalate emulsion copolymer coating 2 containing the ultrafine powder of the hemp stalk core comprises the following weight percentages of the raw materials:

 Polyaminophthalate 20%;

 Dimethyl hydrazide solvent 55%;

 Hydrophilic group solvent 2%;

 Hanma stalk core ultrafine powder 18%.

 Among them, the polyaminophthalate emulsion copolymer coating layer 2 containing the hemp stalk core ultrafine powder has a thickness of 0.012 mm.

 The viscosity index of the coating agent was 33 Pa.s. The coating agent included 35% non-volatiles.

 Example 2:

 The coating agent of the polyamino phthalate emulsion copolymer coating 2 containing the ultrafine powder of the hemp stalk core comprises the following materials:

 Polyaminophthalate 23%;

 Dimethyl phthalamide solvent 57%;

 Hydrophilic group solvent 4%;

Hanma stalk core ultrafine powder 21%. Among them, the polyamino phthalate emulsion copolymer coating layer 2 containing the hemp stalk core ultrafine powder has a thickness of 0.0185 mm. The viscosity index of the coating agent was 33 Pa.s. The coating agent contains 40% non-volatiles.

 Example 3:

 The coating agent of the polyamino phthalate emulsion copolymer coating layer 2 containing the ultrafine fine powder of the hemp stalk core comprises the following weight percentage of the raw materials, and is prepared by stirring: polyamino phthalate 25%;

 Dimethyl hydrazide solvent 60%; hydrophilic group solvent 5%;

 Hemp stalk core ultrafine powder 25%.

 Among them, the polyaminophthalate emulsion copolymer coating layer 2 containing the hemp stalk core ultrafine powder has a thickness of 0.025 mm. The viscosity index of the coating agent was 33 Pa.s. The coating agent included 45% non-volatiles.

 In the embodiment 1-3, the preparation process of the hemp stalk core ultrafine powder comprises: first processing the hemp stalk core into a coarse powder, and performing pretreatment, followed by refining treatment and activation treatment, and drying after the treatment is completed. After drying, the modification treatment is carried out, and then the micronization treatment is carried out, and finally the separation treatment is carried out to obtain the ultrafine fine powder of the hemp stalk core.

The modification treatment is to carry out polymerization modification by adding a certain amount of diphenylnonane diisocyanate and a small amount of polyol in the hemp stalk core after pulverization and drying. The polyamino phthalate emulsion used in the invention comprises an ultrafine powder of hemp stalk core, and the molecular structure of the polyaminophthalic acid ester contains a polymer compound of NHCOO-unit, and the main principle is to introduce an appropriate amount into the polymer chain. The hydrophilic group spontaneously disperses to form an emulsion under certain conditions, and the PU macromolecule contains a large amount The polar group, which has a strong intermolecular force, results in excellent film formation, a tough and durable film on the fabric, and a certain moisture permeability.

 The reason is: on the one hand, the polar group or the hydrophilic group in the PU, such as an OH, -NHC00-, - C00H, the "chemical ladder stone" of the Hanma stalk core ultrafine powder, etc., so that the water vapor molecules Moving along the ladder from the high humidity side to the low humidity side; in theory, the polymer chain mainly has hydrophilic groups, and as long as the hydrophilic group content and arrangement are appropriate, they can interact with water molecules. By means of hydrogen bonding and other intermolecular forces, the water is adsorbed on the high humidity side, and then desorbed by the hydrophilic group on the polymer chain to the low humidity side. Therefore, moisture permeability is essentially a process of "adsorption-diffusion-transfer-desorption". Hydrophilic groups are called "chemical ladder stones," and in the presence of a pressure difference, the water is directed from one side. Transfer to the other side. This process is also a process of moisture permeability.

 Adding 18~25% of the hemp stalk core ultrafine powder to the polyamino phthalate emulsion coating agent, the added hemp stalk core ultrafine powder has a large number of 0.5~0.2μπι micropores and cracks, and contains more The hydrophilic reactive group forms a copolymer coating gel; the moisture permeability factor containing the ultrafine powder of the hemp stalk core has a large content of cellulose, and has a large amount of hydroxyl groups to make it bind to water molecules, and there are micro-grooves and Micropores increase the moisture absorption area and diffusion area. Compared with the conventional PU coating, the water absorption of the copolymer coating rubber containing the ultrafine powder of the hemp stalk core is increased by about 10%, and the moisture permeability is improved by 1 to 5 times, which greatly improves the interior of the automobile lamp. The external moisture-removing capacity keeps the interior of the lamp lamp with a low humidity and no fog condensation, thus eliminating the adverse effects of light on the lamp; the copolymer coating gel containing the ultrafine powder of the hemp stalk core, After the graft copolymerization, the molecules are rearranged to form a cross-secure space, and the surface is more dense, stable and uniform. The water-resistant strength, light aging resistance, heat aging and the like of the coating film for the large moisture permeability of the automobile lamp are improved.

 Wherein, the manufacturing process of the expanded polytetrafluoroethylene film layer 1 includes:

1) mixing the polytetrafluoroethylene dispersion resin with the liquid squeezing agent in proportion (5: 1) (in which it can Adding a coloring agent to meet the needs of the diversity of film colors);

 2) Insulation is cooked at 30 ° C - 35 ° C, and pressed into a cylindrical blank;

 3) forming a cylindrical blank by calendering;

 4) removing the auxiliary agent by heating at about 100 ° C;

 5) Uniaxial stretching, stretching temperature is about 200 ° C, and then stretching in both directions, the stretching temperature is about 200 ° C;

 6) heat setting, sintering at a temperature of about 340 ° C for 18 min;

 7) Finally, cooling and winding are performed to obtain an expanded polytetrafluoroethylene microporous film.

 The microporous film material of expanded polytetrafluoroethylene (ePTFE) is referred to as "ePTFE film," and "ePTFE" is a sketch of expanded polytetrafluorethylene (expanded polytetrafluorethylene); expanded polytetrafluoroethylene (ePTFE) The microporous film is a high-molecular polymer material film with special function and high added value. It is made by biaxial stretching by a special process. The microfiber of the film forms a micro-fiber of 0.1μπι~18μπι aperture which is transparent inside and outside. The pore is a true gas permeable membrane. The membrane surface can reach several billion micropores per square inch, each micropore diameter is smaller than the minimum value of light mist water droplets (20μπι-100μπι), and much larger than the diameter of water vapor molecules ( 0.0003μπι-0.0004μπι ), which allows water vapor to pass through and the water droplets cannot pass due to the large surface tension. This microporous structure can achieve excellent waterproof and moisture permeability; in addition, because the hole is extremely fine and the longitudinal direction is not curved. Used in the protection of electronic equipment for automobile electrical (lights), although it can make the air in the electrical equipment of the automobile electrical (lights) adjust the pressure balance through the convection of the membrane to achieve non-polluting The dyed dust is dense, but when the car is stopped, it is impossible to prevent or reduce the water vapor in the environment from entering the casing. The humidity of the water vapor staying in the casing is too high, which will seriously affect the performance of the electrical equipment of the automobile electrical (light). .

Therefore, in the present invention, a polyaminophthalate emulsion copolymer coating layer 2 containing a hemp stalk core ultrafine powder is rolled on one side surface of the expanded polytetrafluoroethylene film layer 1 to obtain a large moisture permeability coating film. . The preparation process of the large moisture permeability coating film comprises the following steps:

 a) feeding the coating agent, and adjusting the thickness of the coating is 0.012mm-0.025mm;

 b) unwinding the expanded polytetrafluoroethylene film layer 1 and contacting the coating agent to form a polyamino phthalate emulsion containing the ultrafine powder of the hemp stalk core on the surface of the expanded polytetrafluoroethylene film layer 1 Copolymer coating 2;

 c) heating and drying the polyamino phthalate emulsion copolymer coating 2 containing the ultrafine powder of the hemp stalk core, and heating and drying at a temperature of 80 ° C - 100 ° C, the role of volatilization to remove the dimercapto amide Solvent and solvent recovery treatment;

 d) Store in a temperature of 20 ° C -40 ° C for at least 24 h of curing, that is, to obtain a large moisture permeability coating film.

 Wherein, the coating contains a hydrophilic group and a water molecule, and after being adsorbed on the high humidity side by hydrogen bonding and other intermolecular forces, the hydrophilic group on the polymer chain is transferred to the low humidity side to be desorbed. . Therefore, the moisture permeability is essentially a "adsorption" on the surface of the hydrophilic group polyaminophthalate coating, and the water vapor molecules - water molecules diffuse outward in the hydrophilic group polyurethane coating - water The molecule "desorbs" at the interface interface between the hydrophilic group polyaminophthalate coating and the expanded polytetrafluoroethylene film - the water molecules enter the micropores of the expanded polytetrafluoroethylene film to discharge moisture to the external environment. , the process of hydrophilic groups

"Chemical step stone,, in the presence of a pressure difference, the water is transferred from one side to the other side. This process is also a moisture permeable process.

After extensive tests, it was found that the moisture permeability of the water vapor discharged from the coating side to the expanded polytetrafluoroethylene membrane side was greater than the moisture permeability of the water vapor discharged from the lateral side of the expanded polytetrafluoroethylene membrane. The difference in the wet direction results in a difference in the amount of moisture permeation. The amount of moisture permeation from the side of the coating is about 30 to 50% more than the amount of moisture in the casing from the side of the expanded polytetrafluoroethylene film. The coating film is applied to the casing of the automobile lamp, and the coating side of the coating film is directed into the casing of the automobile lamp, and the coating film is applied. The expanded polytetrafluoroethylene film faces the outside atmosphere; thus, the water vapor in the casing of the automobile lamp is continuously discharged, and the characteristics of continuously discharging water vapor from the inside of the casing to the external environment are exhibited, when the automobile lamp is working, When the temperature inside the casing is high, the more active the hydrophilic polymer segment of the coating, the faster the adsorption, diffusion and desorption of water vapor molecules are discharged, and the humidity in the casing of the automobile lamp is greatly reduced, so that there is no condensation. The condition is such that the air in the casing is dry, and no foggy water is generated on the mirror surface or the surface of the smooth electronic component in the casing of the automobile lamp, so that the performance of the automobile lamp can be exerted.

 The invention has good moisture absorption and moisture permeability performance, and the moisture permeability factor containing the ultrafine powder of the hemp stalk core has a large content of cellulose, and has a large amount of hydroxyl groups to make it have more binding groups with water molecules, and there are micro grooves and micropores at the same time. Increased moisture absorption area and diffusion area. The application of the invention can ensure the absence of fog condensation in the casing of the automobile lamp, so that the electrical performance is not affected by the humid air environment, and the traditional method of adjusting the humidity control in the casing is completely subverted.

 A large number of tests have found that the moisture permeability of water vapor discharged from the coating side to the expanded polytetrafluoroethylene membrane side is greater than the moisture permeability of the water vapor discharged from the lateral side of the expanded polytetrafluoroethylene membrane, and two moisture permeability directions. The difference in the amount of moisture permeability is that the amount of moisture permeation from the coating side is about 30 to 50% larger than that from the lateral direction of the expanded polytetrafluoroethylene film, and the moisture permeability in both directions is utilized. A huge difference in the amount, the coating film is applied to the casing of the automobile lamp, the coating side of the coating film is directed into the casing of the automobile lamp, and the expanded polytetrafluoroethylene film of the coating film faces outward The atmosphere; the water vapor in the casing of the automobile lamp is continuously discharged, and the characteristic of continuously discharging water vapor from the inside of the casing to the external environment is exhibited. When the automobile lamp is working, when the temperature inside the casing is high, the coating is performed. The more active the hydrophilic polymer segment of the layer, the faster the adsorption, diffusion and desorption of water vapor molecules are discharged. The humidity in the casing of the automobile lamp is greatly reduced, so that the condensation condition is not provided, and the air in the casing is dried. Car headlight housing A mirror smooth surface of electronic components or there will fog phenomenon, so that performance of the car headlights to play.

The present invention exhibits a characteristic of continuously discharging water vapor in one direction from the inside of the casing to the external environment, so that the casing The internal air drying completely changes the mode in which the water vapor in the casing of the previous automobile lamp is scattered by the principle of air convection.

 The invention not only has good adsorption performance, but also can block the infiltration of rain and dust, so that the dust-proof level of the automobile lamp lamp reaches a pollution-free level; the coating side of the coating film is directed into the casing of the automobile lamp, the coating The expanded polytetrafluoroethylene film of the film faces the outside atmosphere; thus the water vapor in the casing of the automobile lamp is continuously discharged from the energy source, and the characteristic of continuously discharging water vapor from the inside of the casing to the external environment is exhibited, when the automobile car When the lamp is working, when the temperature inside the casing is high, the hydrophilic polymer segment of the coating is more active, and the faster the adsorption, diffusion and desorption of water vapor molecules are discharged, the humidity in the casing of the automobile lamp is greatly reduced. Without the condensation condition, the air inside the casing is dry, and the surface of the mirror or the smooth electronic components in the casing of the automobile lamp is free from fogging, so that the performance of the automobile lamp can be exerted; The stalk core ultra-fine powder can absorb the volatile matter generated by the plastic shell of the lamp due to heat, which is beneficial to the mirror reflection of the lamp to maintain light reflection performance.

 The invention also has excellent anti-ultraviolet performance, and the invention solves the defects in the background art, and the performance of the material fully satisfies the performance of automobile lamps and other small precision electronic devices (mobile phones, navigation terminals, microcomputers, etc.). Reliable performance, comprehensive protection requirements in waterproof, dustproof, oil proof, moisture permeable, anti-oxidation solution corrosion.

 It is also possible to further develop end products for engineering use, such as "coating film patches for large moisture permeability of automobile lamps", "coating film plugs (caps) for large moisture permeability of automobile lamps, etc., etc. The products with high value-added products are more convenient for industrialized manufacturing of standardized terminal products.

 Further reducing the design and manufacturing cost of the automobile lamp in eliminating the influence of water vapor on its performance, the casing shape is simplified.

It also has the characteristics of non-breathable body (allowing water vapor molecules to be discharged) and high water penetration resistance. The water pressure resistance of the coating film has reached 10000mm height water column (relative pressure lOOKPa pressure). The membrane can withstand the impact of deep water soaking or impact water during driving, so that the inside of the casing is kept dry without immersion.

 The above is only the embodiment of the present invention, and thus does not limit the scope of the invention, and the equivalent structure or equivalent process transformation made by using the content of the specification of the present invention, or directly or indirectly applied to other related technical fields, The same is included in the scope of patent protection of the present invention.

Claims

The invention provides a large moisture permeability coating film, comprising: a base film layer and a coating layer, wherein the base film layer is an expanded polytetrafluoroethylene film layer coated on the expanded polytetra The coating on the fluoroethylene film layer is a polyamino phthalate emulsion copolymer coating containing the ultrafine powder of the hemp stalk core;  The coating agent of the polyaminophthalate emulsion copolymer coating containing the hemp stalk core ultrafine powder comprises the following materials:  Polyaminophthalate 20%_25%;  Dimethyl hydrazide solvent 55% _60%;  Hydrophilic group solvent 2%-5%;  Hemp stalk core ultrafine powder 18%-25%.  O. 025mm - 0. 025mm. The thickness of the polyurethane acrylate emulsion coating having a thickness of 0. 012mm - 0. 025mm.  The large moisture permeability coating film according to claim 1, wherein the coating agent has a viscosity index of 33 Pa.s.  The large moisture permeability coating film according to claim 1, wherein the coating agent contains 35% to 45% of a nonvolatile matter.  The large moisture permeability coating film according to claim 1, wherein the manufacturing process of the hemp stalk core ultrafine powder comprises: first processing the hemp stalk core into a coarse powder, and pretreating Then, the refining treatment and the activation treatment are sequentially performed, and after the completion of the treatment, drying is performed, and then the modification treatment is carried out, and then the refining treatment is carried out, and finally, the separation treatment is performed to obtain the ultrafine powder of the hemp stalk core.  The large moisture permeability coating film according to claim 5, wherein the modification treatment is to add diphenylnonane diisocyanate and polyol polymerization modification in the hemp stalk core after pulverization and drying. .  The large moisture permeability coating film according to any one of claims 1 to 6, wherein the preparation process of the large moisture permeability coating film comprises the following steps:  a) feeding the coating agent and adjusting the thickness of the coating;  b) unwinding the expanded polytetrafluoroethylene film layer and contacting the coating agent to form a polyaminophthalate emulsion copolymer coating on the surface of the expanded polytetrafluoroethylene film layer containing the ultrafine powder of the hemp stalk core Floor;  c) heating and drying the polyamino phthalate emulsion copolymer coating containing the ultrafine powder of the hemp stalk core; d) curing the mixture to obtain a large moisture permeable coating film.  O. 025mm - 0. 025mm。 The thickness of the coating is 0. 012mm - 0. 025mm.  The large moisture permeability coating film according to claim 7, wherein in the step c), the heating and drying temperature is from 80 ° C to 100 ° C. The large moisture permeability coating film according to claim 7, wherein in step d), the cooked Curing is stored at a temperature of 20 ° C -40 ° C environment at least 241 ^