JP2006176615A - Coating agent for polyolefin-based resin molded article and molded article coated therewith - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coating agent capable of imparting a coated film having good moldability and adhesion, and also having abrasion resistance, chemical resistance or the like to a polyolefin-based resin molded article especially usable as an interior material of a car such as a sheet and a leather; and to provide the molded article having the coated film formed thereon. <P>SOLUTION: The coating agent for the polyolefin-based resin molded article comprises a primary coating agent obtained by compounding a crosslinking agent reactable with a functional group in a water-based polyurethane resin having a carboxy group and/or a hydroxy group in the molecule with a compounded product comprising the resin, a water-based nonhalogen polyolefin-based resin having a carboxy group in the molecule, and a matting agent, and a secondary coating agent obtained by compounding a crosslinking agent reactable with a functional group in a water-based polyurethane resin having a carboxy group and/or a hydroxy group in the molecule with a compounded product comprising the resin and a matting agent. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a coating agent and a molded article coated with the coating agent. Specifically, when applied to a polyolefin resin molded article such as a sheet or leather, the moldability and adhesion are good, and wear resistance and chemical resistance. The present invention relates to a coating agent capable of forming a uniform matte film having excellent antiglare properties and a polyolefin resin molded article having such a film.

  Conventionally, a soft polyvinyl chloride resin has been often used as a molded article such as a sheet or leather used for automobile interior parts. However, deterioration of discoloration and embrittlement due to plasticizers used in large quantities to impart flexibility have been regarded as problems from soft polyvinyl chloride resin molded articles.

  For this reason, recently, polyolefin-based resin molded products have been used in place of soft polyvinyl chloride resin molded products as molded products such as sheets or leather used for automobile interior parts and the like. This is because polyolefin resin, unlike soft polyvinyl chloride resin, can give flexibility without using a plasticizer, and its specific gravity is smaller than soft polyvinyl chloride resin, reducing the weight of interior parts. This is because it has advantages such as being recyclable and recyclable.

  In general, an olefinic thermoplastic elastomer constituting a polyolefin resin molded product used for automobile interior parts and the like is an ethylene-propylene copolymer and an ethylene-containing third component having a partially crosslinked structure. A main component is propylene terpolymer (EPDM), and an antistatic agent, a heat stabilizer, an ultraviolet absorber, a pigment, and the like are blended therein. Molded products made of these olefinic thermoplastic elastomers are generally difficult to paint on the surface, and often have poor physical properties such as adhesion and wear resistance. This is due to the inert surface of the polyolefin-based thermoplastic elastomer.

  Conventionally, for the purpose of solving the above-mentioned problems, the surface of a polyolefin resin is physically or chemically activated by corona discharge treatment or the like, and then a primary coating agent comprising an organic solvent solution of a chlorinated polyolefin resin, Alternatively, there has been proposed a method of coating a secondary coating agent, which is a topcoat agent, after coating a secondary curing type primary coating agent comprising an organic solvent solution of polyester resin and polyisocyanate, polyurethane resin and polyisocyanate. (Patent Documents 1, 2 and 3).

  In recent years, automotive interior parts have become more sophisticated, and there are fewer parts made of olefinic thermoplastic elastomer molded products. For example, as seen in door trims, woven fabrics are bonded to olefinic resin molded products. A composite material bonded together using is often used. For this reason, surface treatment agents for olefin-based resin molded products are required to have resistance to the solvent contained in the adhesive used for bonding or heat-resistant creep resistance that can withstand temperature rise in the automobile interior. For the purpose of satisfying the requirements, a secondary curing type coating agent comprising an organic solvent solution of polyester resin and polyisocyanate, polyurethane resin and polyisocyanate has been mainly used.

  On the other hand, the market wants a water-based coating agent without using an organic solvent for the purpose of reducing VOC (volatile organic compound) emissions, and proposes an aqueous matting treatment agent made of an aqueous polyurethane resin containing polyolefin polyol. However, the heat resistance creep resistance and durability properties were insufficient (Patent Document 4).

Furthermore, the present invention relates to a non-chlorine-based aqueous polyolefin resin composition capable of blending a water-based urethane resin and a water-based blocked isocyanate, characterized in that a fluorine-based surfactant is blended with an aqueous resin composition containing a non-chlorine-based modified polyolefin. Proposals have also been made (Patent Document 5), but when these are applied to the field of polyolefin resin molded products as automobile interior parts, there is a problem that required moldability cannot be maintained.
JP-A-63-272547 JP 7-247381 A JP 7-247382 A JP 2003-342549 A JP-A-8-3376

  In view of the above, the present invention has been studied to solve the problems of the above-mentioned conventional coating agents for polyolefin resin molded products, and as a result, it is used for polyolefin resin molded products such as sheets and leather. It is an object of the present invention to provide a coating agent for polyolefin resin molded products and a molded product comprising the coating agent, which can obtain a matte film having good wear resistance and chemical resistance.

  The invention according to claim 1 is a composition comprising an aqueous polyurethane resin having a carboxyl group and / or a hydroxyl group in the molecule, a non-chlorine aqueous polyolefin resin having a carboxyl group in the molecule, and a matting agent. And a primary coating agent obtained by blending a crosslinking agent capable of reacting with a functional group in the resin, a water-based polyurethane resin having a carboxyl group and / or a hydroxyl group in the molecule, and a matting agent. A coating agent for a polyolefin-based resin molded article comprising a secondary coating agent obtained by blending a crosslinking agent capable of reacting with a functional group in the resin.

  The invention according to claim 2 is the invention according to claim 1, wherein the water-based polyurethane resin having a carboxyl group and / or a hydroxyl group in the molecule and a carboxyl in the molecule are resin components constituting the primary coating agent. The amount of the non-chlorine aqueous polyolefin resin having a group is in the range of 10:90 to 50:50 in terms of the weight fraction with respect to each solid content.

  The invention according to claim 3 is the invention according to claim 1 or 2, wherein the crosslinking agent used together with the resin component constituting the primary coating agent is one selected from polyisocyanate, carbodiimide, aziridine, and oxazoline, The amount used is 10 to 22 parts by weight based on 100 parts by weight of the solid content of the resin component constituting the primary coating agent.

  The invention according to claim 4 is the invention according to claim 1, wherein the crosslinking agent used together with the resin component constituting the secondary coating agent is one selected from polyisocyanate, carbodiimide, aziridine and oxazoline, The amount used is 2 to 15 parts by weight with respect to 100 parts by weight of the solid content of the resin component constituting the secondary coating agent.

  The invention according to claim 5 is characterized by a polyolefin resin molded product having a coating film formed on the surface using the coating agent for polyolefin resin molded product according to claim 1.

  According to the coating agent for polyolefin-based resin molded product described in the above-mentioned claim of the present invention, a sheet. A matte coating film having good moldability and adhesion, excellent wear resistance, chemical resistance, and the like can be formed on the surface of a polyolefin resin molded product such as leather.

  The present invention will be described in detail below. This invention uses, as a primary coating agent, a composition comprising a water-based polyurethane resin, a non-chlorine water-based polyolefin resin, and a matting agent to which a crosslinking agent capable of reacting with the functional group of these resins is added. After coating this onto a polyolefin resin substrate and drying to form a primary coating film, the urethane coating is then formed on the primary coating film with a composition comprising a water-based polyurethane resin and a matting agent. A composition to which a crosslinking agent capable of reacting with a functional group of a resin is added as a secondary coating agent, and then dried to provide good moldability and adhesion as described above, and wear resistance. Thus, it is possible to obtain a polyolefin-based resin molded article having a matte film excellent in chemical resistance.

  In applying the primary coating agent to the polyolefin-based resin base material as described above, it is preferable to perform corona discharge treatment on the surface of the base material before the application from the viewpoint of improving adhesion.

  Next, the primary coating agent will be described. The non-chlorine aqueous polyolefin resin to be mixed improves the initial adhesion to the polyolefin resin substrate, and after heating and drying, the mixed aqueous polyurethane resin and aqueous polyolefin resin are By cross-linking together, it is possible to fix and adhere to the surface of the base material, and as a result, the heat resistant creep resistance is improved. Further, the water-based polyurethane resin and the polyolefin resin used are in the range of 10:90 to 50:50, preferably in the range of 20:80 to 40:60, by weight fraction with respect to each solid content, Good moldability and adhesion can be maintained at the same time.

  At this time, if the weight ratio of the water-based polyurethane resin and the polyolefin resin used in the primary coating agent to the solid content is less than 10%, heat-resistant creep can be achieved even if the type and amount of the crosslinking agent are changed. If the property is insufficient and the amount is more than 50%, the initial adhesion to the substrate is insufficient, and as a result, there is a risk that the stretch rate of the coating film varies during molding, resulting in a non-uniform coating film. is there.

  Furthermore, the secondary coating agent will be described. Since the water-based polyurethane resin to be blended and the water-based polyurethane resin used for the primary coating agent both contain the water-based polyurethane resin, the adhesion with the primary coating layer is good. In addition, heat resistance and chemical resistance can be improved by two-component crosslinking. Moreover, these coating agents can improve durability properties such as light resistance and hydrolysis resistance by crosslinking.

  On the other hand, the kind and amount of the crosslinking agent used for the primary coating agent and the secondary coating agent are also important. The cross-linking agent is selected depending on the reactive group of the aqueous resin to be reacted. A carbodiimide, aziridine, or oxazoline-based crosslinking agent may be used when reacting with a carboxyl group contained in the aqueous resin, and a polyisocyanate-based crosslinking agent may be used when reacting with a hydroxyl group.

  The amount of the crosslinking agent used in the above is different between the primary coating agent and the secondary coating agent. The amount of the crosslinking agent used in the primary coating agent is 10 to 22 parts by weight, preferably 15 to 20 parts by weight, based on 100 parts by weight of the solid content of the aqueous resin used in the primary coating agent. If the amount of the cross-linking agent is less than 10 parts by weight, the adhesive adhesion after cross-linking with the olefin substrate becomes insufficient, and if it exceeds 22 parts by weight, the water-based polyurethane resin and polyolefin used for the primary coating agent Even if the weight ratio with the resin is adjusted, the elongation of the coating film during molding becomes too low, and whitening and cracking occur on the surface of the coating film, which is not preferable.

  The amount of the crosslinking agent used in the secondary coating agent is 2 to 15 parts by weight, preferably 5 to 10 parts by weight, based on 100 parts by weight of the solid content of the water-based polyurethane resin used in the secondary coating agent. . If the amount of the crosslinking agent is less than 2 parts by weight, the chemical resistance of the coating film surface becomes insufficient, and if it is more than 15 parts by weight, the elongation of the coating film becomes too low at the time of molding. Whitening and cracking occur, which is not preferable.

  In the present invention, the water-based polyurethane-based resin can be produced using a combination of many materials, and is not particularly limited. The water-based polyurethane resin can be blended with emulsions or dispersions of other polymer resins, or can be copolymerized or graft-polymerized with these monomers. For example, silicone resin, acrylic resin, epoxy resin, cellulose resin, nitrile rubber or the like can be blended according to the purpose, acrylic monomer can be graft polymerized, or reactive silicone resin can be copolymerized.

  An example of the production of these resins is as follows. The water-based polyurethane resin is a polyol having a terminal hydroxyl group, that is, a polyester polyol having an average molecular weight of about 500 to 5,000, a polyether polyol, a polyε-caprolactone polyol, a polycarbonate diol, or the like alone or It can be obtained by heating the mixture, the organic diisocyanate and the chain extender. In the case of an aqueous polyurethane resin containing an anionic salt-forming group and a carboxyl group in the molecule for the purpose of emulsification and dispersion after neutralization with an amine or the like, 2,2- Diglycolic acid represented by dimethylolpropionic acid, 2,2-dimethylolbutanoic acid and 2,2-dimethylollactic acid may be used.

  The water-based polyurethane resin is preferably one having the average molecular weight in the range of 30,000 to 2,000,000 by using the above-described monomer component and mixing and reacting so that no isocyanate group remains at the terminal. When limited to applications such as automotive interior parts, polycarbonate diol is mainly used as the polyol component for the purpose of improving durability against light, heat and water, and aliphatic and alicyclic types of diisocyanate components are used. It is desirable to use it.

  Examples of the method for producing a water-based polyurethane resin in the present invention include a forced emulsification method using a surfactant, an acetone method, a ketimine ketazine method, an ionomer method in which an anionic salt-forming group is contained and emulsified and dispersed by neutralization. A method may be used, and when an organic solvent is used during the reaction, it is necessary to remove it after the reaction.

  Next, as the non-chlorine aqueous polyolefin resin in the present invention, the end of an amorphous polyolefin having a molecular weight of about 2,000 to 500,000 consisting of low density polyethylene, high density polyethylene, polypropylene, polyethylene propylene copolymer or the like Type added by graft reaction of α, β-unsaturated carboxylic acid represented by maleic acid, phthalic acid, itaconic acid and their acid anhydrides or the acid anhydrides on the side chain, such as acrylic and styrene Graft polymerization modified products with monomers can be used, and these are usually dissolved in an organic solvent solution such as toluene or methylcyclohexane, and then converted to water by forced emulsification using a surfactant or basic substance, and the solvent is removed. You can get it.

  As the matting agent, conventionally known silica fine powder, inorganic fine powder such as talc and mica, organic fine powder represented by polyurethane beads, acrylic beads, silicon powder, fluorine powder, and the like may be used.

  Furthermore, it is possible to add additives, such as a coloring agent, a leveling agent, an antifoamer, a thickener, to the coating agent of this invention as needed. Moreover, the coating method of the obtained coating agent can also perform the process by the gravure coater to a sheet-like olefin base material, or the spray process to a molded article, and the coating film after drying normally will be about 2-10 micrometers. The coating film is dried by heating to around 100 ° C.

EXAMPLES Hereinafter, although this invention is demonstrated in detail by a manufacture example and an Example, this invention is not limited at all by these manufacture examples and examples. All the parts are parts by weight.
(Production Example 1) (Water-based polyurethane resin dispersion PUD-1)

  1500 parts of polycarbonate diol having an average molecular weight of 2000 having hydroxyl groups at both ends and 67 parts of 2,2-dimethylolpropionic acid were blended and mixed uniformly under a nitrogen stream. Next, 524 parts of dicyclohexylmethane 4,4′-diisocyanate was added to this mixture and heated at 110 ° C. for 3 hours, and this was added to 7500 parts of ion-exchanged water at 20 ° C. containing 50.5 parts of triethylamine. The mixture was vigorously stirred and emulsified using a mixer.

Next, 127.5 parts of 3-aminomethyl-3,5,5'-trimethylcyclohexylamine mixed with 1280 parts of ion-exchanged water was added and held for 30 minutes, and then the solid content concentration was 20.5% and the viscosity was 20 mPa · s. An s / 30 ° C. aqueous polyurethane resin dispersion PUD-1 (hereinafter referred to as PUD-1 dispersion) was obtained.
(Production Example 2) (Water-based polyurethane resin dispersion PUD-2)

  1500 parts of polycarbonate diol having an average molecular weight of 2000 having hydroxyl groups at both ends and 74 parts of 2,2-dimethylolbutanoic acid were blended and uniformly mixed under a nitrogen stream. Next, 524 parts of dicyclohexylmethane 4,4′-diisocyanate was added to this mixture and heated at 110 ° C. for 3 hours, and this was added to 7500 parts of ion-exchanged water at 20 ° C. containing 50.5 parts of triethylamine. The mixture was vigorously stirred and emulsified using a mixer.

  Next, 110.5 parts of 3-aminomethyl-3,5,5'-trimethylcyclohexylamine mixed with 1280 parts of ion-exchanged water and 10.5 parts of diethanolamine are added and held for 30 minutes, and then a solid content concentration of 20 An aqueous polyurethane resin dispersion PUD-2 (hereinafter referred to as PUD-2 dispersion) having a viscosity of 1% and a viscosity of 12 mPa · s / 30 ° C. was obtained.

  A solid resin concentration of 30 obtained by forcibly emulsifying a partially maleated and partially acrylic-modified solution into a polyolefin resin composed of ethylene propylene dissolved in methylcyclohexane, and then removing methylcyclohexane used in the reaction. %, An aqueous polyolefin resin emulsion OFE-3 (hereinafter referred to as OFE-3 emulsion liquid) having a viscosity of 30 mPa · s / 30 ° C., the aqueous polyurethane resin dispersion PUD-1 obtained in Production Example 1 and the above The aqueous polyurethane-based resin dispersion PUD-2 obtained in Production Example 2 is blended in the ratios shown in A to C of Table 1, and a crosslinking agent is further added to add the primary coating agent and A to C of Table 1 The next coating agent was obtained.

  Next, a thermoplastic polyolefin sheet that has been subjected to corona discharge treatment to increase the surface activity to a wetness index of 45 dyne / cm is used as a base material, and the primary coating agent obtained above is applied to the base material surface with a 120 mesh gravure roll. After coating twice, it was dried at 100 ° C. for 1 minute. Further, on this primary coating film, the secondary coating agent was applied twice with a 120 mesh gravure roll, and then dried at 100 ° C. for 1 minute to form a secondary coating film. Thereafter, aging was carried out at 80 ° C. for 24 hours to form a coating film laminated on a sheet made of polyolefin resin.

  In the crosslinking agent described in Table 1, XL-29SE is a carbodiimide compound having a solid concentration of 50% manufactured by Union Carbide, USA, and Aquanate 210 is a solid content concentration manufactured by Nippon Polyurethane Industry Co., Ltd. 100% polyisocyanate compound for water-based paints.

Furthermore, E-220A used as a matting agent is a silica fine powder manufactured by Nippon Silica Kogyo Co., Ltd., OK-412 is a silica fine powder manufactured by Digusa, USA, and Gantz Pearl GM-S0370 is manufactured by Gantz Kasei. Acrylic beads. Moreover, all the component ratios in Table 1 are weight ratios in solid content.
Comparative Example 1

Like Example 1, it mix | blends by the ratio shown to the mixing | blending No.D and E of Table 1, and also adds a crosslinking agent, and also mix | blends the primary coating agent and secondary coating agent of mixing | blending No.D and E of Table 1. Obtained. Using these coating agents, a coating film laminated on a sheet made of polyolefin resin was formed in the same manner as in Example 1.
Comparative Example 2

  Like Example 1, it mix | blends by the ratio shown to mixing | blending No.F of Table 1 to I, and also adds a crosslinking agent, and also mix | blends the primary coating agent and secondary coating agent of mixing | blending No.F-I of Table 1. Obtained. Using these coating agents, a coating film laminated on a sheet made of polyolefin resin was formed in the same manner as in Example 1.

  Next, physical properties tests such as heat-resistant creep resistance, moldability, and chemical resistance were performed on the coating films obtained in Example 1 and Comparative Examples 1 and 2. The results are shown in Table 1. These physical property test methods and evaluation methods are as follows.

  (1) Heat-resistant creep test: Two coating films laminated on a sheet made of polyolefin resin were sampled in a length of about 15 cm with a width of 2.5 cm in the coating longitudinal direction, and the films of these two specimens After bonding the surfaces to each other with a length of 10 cm with an instantaneous adhesive (cyanoacrylate), the surface is suspended in a piece of unbonded 5 cm portion of the specimen in a gear oven set at 110 ° C., and the other piece is 200 gf A test piece was peeled off after being applied with a load for 1 hour. Δ: Peeled to some extent between the coating agent and the substrate. X: The coating agent completely peeled from the substrate, and the specimen was detached. A three-stage evaluation was performed.

  (2) Formability test: The coating film laminated on the sheet made of polyolefin resin was set in a convex vacuum forming machine, and the surface change when the sheet was stretched 150% at a surface temperature of 150 ° C. was as follows: Five grades were evaluated. 5: No molding cracking or whitening phenomenon. 4: Although there is no molding crack, there is a partial whitening phenomenon. 3: Partially cracked and whitened. 2: There are some molding cracks, and there are many whitening phenomena on the entire surface. 1: There is a molding crack on the entire surface.

(3) Chemical resistance test: A coating film laminated on a sheet made of a polyolefin resin is set in a wear tester type II defined in JIS L 0849, and immersed in isopropyl alcohol as a friction element to be approximately 100% wet. The coated gold surface No. 3 was attached, and the coating film surface state after reciprocating friction 100 times under a load of 200 gf was evaluated in five stages as follows.
5: No change. 4: There is a slight rubbing trace. 3: There are friction marks. 2: The coating film is partially peeled off by friction. 1: The coating film peeled off due to friction.

  (4) Surface strength confirmation test after light resistance test: A coating film laminated on a sheet made of polyolefin resin is set in an ultraviolet carbon arc fluorescent light resistance tester at a black panel temperature of 83 ° C. and irradiated for 1000 hours. The surface of the coating film was scratched with a nail, and the following five-step evaluation was performed from the ease of scratching. 5: Not scratched. 4: Almost no scratches. 3: Although scratched, the coating film is not peeled off from the substrate. 2: The coating film is partially peeled from the substrate. 1: The coating film is completely peeled off from the substrate.

From the results of Table 1 above, all of the coating films composed of Formulation Nos. A, B, and C of Example 1 of the present invention showed good results. On the other hand, the coating films composed of Nos. D to I of Comparative Examples 1 and 2 were inferior in all tests such as heat-resistant creep resistance and moldability.

Claims (5)

  A compound comprising an aqueous polyurethane resin having a carboxyl group and / or a hydroxyl group in the molecule; a non-chlorine aqueous polyolefin resin having a carboxyl group in the molecule; and a matting agent; and a functional group in the resin Can react with the functional groups in the resin in a composition consisting of a primary coating agent obtained by blending a reactive crosslinking agent, an aqueous polyurethane resin having a carboxyl group and / or a hydroxyl group in the molecule, and a matting agent. A coating agent for polyolefin-based resin molded products, comprising a secondary coating agent obtained by blending a suitable crosslinking agent. The amounts of the water-based polyurethane resin having a carboxyl group and / or hydroxyl group in the molecule and the non-chlorine water-based polyolefin resin having a carboxyl group in the molecule, which are the resin components constituting the primary coating agent, The coating agent for polyolefin-based resin molded products according to claim 1, wherein the weight ratio with respect to the solid content is in the range of 10:90 to 50:50.   The crosslinking agent used together with the resin component constituting the primary coating agent is one selected from polyisocyanate, carbodiimide, aziridine, and oxazoline, and the amount used is 100 parts by weight of the solid content of the resin component constituting the primary coating agent. The coating agent for polyolefin resin molded products according to claim 1 or 2, wherein the coating agent is 10 to 22 parts by weight.   The crosslinking agent used together with the resin component constituting the secondary coating agent is one selected from polyisocyanate, carbodiimide, aziridine, and oxazoline, and the amount used is 100 parts by weight of the solid content of the resin component constituting the secondary coating agent The coating agent for polyolefin-based resin molded products according to claim 1, wherein the amount is 2 to 15 parts by weight based on the weight. A polyolefin-based resin molded product comprising a coating film formed on the surface using the coating agent for a polyolefin-based resin molded product according to claim 1.