JPS6146489B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a polyester resin-coated molded article.

Polyester resins, especially those mixed with glass fibers, have strong mechanical strength and tensile strength, and are used for various purposes. It is also known to coat articles with polyester resins. However, since the polyester molding resin is a liquid, a mold such as a wooden mold, a plaster mold, or a metal mold is required for molding. After molding, it had to be removed from the mold and then painted and molded.

As a result of research into methods and materials for encasing and molding without the need to remove the mold after molding, the inventor found that the object could be achieved by using a special foam, and developed the present invention. It was completed.

Synthetic resin foam is lightweight, and when it is used as a mold and coated with polyester resin,
This is highly advantageous as there is no need to remove the foam. However, when polystyrene foam is used as the foam, it is preferable because it has appropriate rigidity and good shape retention, but it has the disadvantage that it can be dissolved by solvents such as styrene monomers contained in polyester molding resin. There is. In contrast, foamed polyolefin resins such as polypropylene are not attacked by solvents such as styrene monomers, but are flexible and have poor shape retention, making them unsuitable as molds for coating polyester resins. .
As a result of intensive research in order to obtain a foam that has appropriate rigidity, good shape retention, and is not attacked by the solvent contained in polyester molding resin,
The inventors have found that resin foams of special composition may be suitable for this purpose.

In the present invention, a polybasic acid and a polyhydric alcohol are added to the surface of a thermoplastic resin foam molded product made by foam-molding thermoplastic resin particles obtained by reacting polypropylene resin particles with a vinyl aromatic monomer to carry out graft polymerization and crosslinking polymerization. The gist of this invention is a method for producing a polyester resin-coated molded article, which is characterized by coating and curing a polyester molding resin obtained by condensing and polymerizing a polyester resin with a biruni monomer added as a solvent. .

The thermoplastic resin foam molded product used in the method of the present invention is made by suspending polypropylene resin particles and a vinyl aromatic monomer in an aqueous medium, and then polymerizing the resulting particles by adding a foaming agent to the resulting particles to form the foamed product. is used. Here, examples of the polypropylene resin particles include polypropylene, a random copolymer of ethylene and propylene, and an ethylene-propylene-polyene copolymer. Specific examples of the above polypropylene resin are as follows. Polypropylene homopolymer, random copolymer of ethylene and propylene, random copolymer of propylene and butene, propylene/vinyl acetate copolymer, propylene/vinyl chloride copolymer,
Propylene/methyl methacrylate copolymer,
It is a copolymer or mixture of propylene vinyl acetate copolymer, ethylene/propylene rubber, propylene polyisobutylene, butyl rubber, polybutene, polybutadiene, etc. In these polypropylene resins, in the case of copolymers or mixtures, the polypropylene content accounts for 50% by weight or more. In the case of an ethylene-propylene-polyene copolymer, the polyenes include hexadiene-1,4, hexadiene-1,5, heptadiene-1,6, 2-methyl-pentadiene-1,
4, octadiene-1,9,6-methylheptadiene-1,5,9-ethylundecadiene-1,
9, octatriene-1,4,7, ethylidene norbornene, dicyclopentadiene, cyclooctadiene-1,4, and cyclohexadiene. Therefore, ethylene 2 to 50% by weight, propylene 50 to 80% by weight, polyene compound
A resin having a composition of 0.5 to 20% by weight is preferably used.

On the other hand, vinyl aromatic monomers include styrene, α-methylstyrene, ethylstyrene, chlorostyrene, bromostyrene, vinyltoluene,
Monomers such as vinyl xylene, isopropyl xylene, etc. or mixtures thereof, or monomers such as methyl methacrylate and divinylbenzene that can be copolymerized with vinyl aromatic monomers containing 50% by weight or more of these vinyl aromatic monomers. For example, a mixture of

The above polypropylene resin particles and vinyl aromatic monomer are mixed in an aqueous medium containing a suspending agent such as benzoyl peroxide, t-butyl perbenzoate, lauroyl peroxide, t-butyl peroxy-2-ethylhexanate, azo When one or more catalysts such as bisisobutylnitrile, dicumyl peroxide, and t-butylcumyl peroxide are added and reacted by heating, the vinyl aromatic monomer permeates into the polyolefin resin particles and co-acts. Polymerized, graft-polymerized and cross-linked thermoplastic resin particles are obtained. In the above reaction, the polypropylene resin particles are generally 20 to 80% by weight, and the vinyl aromatic monomer is 80 to 80% by weight.
20% by weight is used, but if the amount of the vinyl aromatic monomer is less than the above amount, the expansion ratio of the resulting foam will not increase, making it impossible to obtain a foam with a high expansion ratio. If the amount of the group monomer is too large, properties such as oil resistance, heat resistance, and solvent resistance of the resulting foam will deteriorate. The most preferred ratio is 50 to 30% by weight of polypropylene resin particles and 70 to 50% by weight of vinyl aromatic monomer.

When the above thermoplastic resin particles are impregnated with a blowing agent such as propane, butane, pentane, hexane, methyl chloride, dichlorodifluoromethane, etc. under pressure in an aqueous suspension according to a conventional method, expandable thermoplastic resin particles are obtained. is obtained. By pre-foaming this and heat-foaming and fusing the pre-expanded particles in a predetermined mold cavity, a thermoplastic resin foamed molded article having a predetermined shape can be obtained. Such a molded product can also be obtained by secondary processing a foamed sheet or a plate-shaped body obtained by extruding and foaming the thermoplastic resin particles with a foaming agent using an extruder.

In the method of the present invention, the surface of the thermoplastic resin foam molded article described above is coated with a polyester resin. Polybasic acids used in polyester resins include maleic anhydride, fumaric acid, adipic acid, phthalic anhydride,
Isophthalic acid, tetrachlorophthalic anhydride or a mixture thereof, etc., and polyhydric alcohols include ethylene glycol, propylene glycol,
1,3-butylene glycol, diethylene glycol, dipropylene glycol, neopentyl glycol, bisphenol dioxyethyl ether, glycerin, pentaerythritol, mannitol, or mixtures thereof are used.

The above polybasic acid and polyhydric alcohol are subjected to a polycondensation reaction to obtain a polycondensation resin, and a vinyl monomer is added to the resin in an amount of about 0.6 to 30% by weight as a solvent to form a polyester. Used as resin for use. The amount of vinyl monomer added can be freely selected depending on the desired fluidity viscosity of the polyester molding resin. This resin is a low viscosity liquid,
It is generally used mixed with glass fiber. The glass fiber may be made into cloth. Further, polymethyl methacrylate, polyethylene terephthalate, other fillers, or pigments, dyes, etc. may be appropriately mixed with this resin. The above vinyl monomers include styrene, α-methylstyrene, vinyl acetate, methacrylic acid ester,
Examples include diaryl phthalate and α-chlorostyrene, but styrene is commonly used.

When coating a polyester molding resin on the surface of a thermoplastic resin foam molding and curing it, room temperature is sufficient for the reaction temperature. In this case, it is desirable to use a catalyst such as methyl ethyl ketone perioside, and to use cobalt naphthenate as a reaction promoter if necessary. The curing reaction may be carried out under heating. In this case as well, a catalyst such as benzoyl peroxide is used to carry out the reaction. In addition to the above, examples of the curing catalyst include cyclohexanone peroxide, lauroyl peroxide, di-t-butyl peroxide, t-butyl perbenzoate, cumene hydroperoxide, and the like.

In the method of the present invention, the curing reaction of the polyester is preferably carried out at room temperature, but may also be heated. In the case of heat curing, it is preferable to carry out the reaction at 100°C or lower.

In the method of the present invention, when the polyester molding resin is applied to the surface of the thermoplastic resin foam molding, the vinyl monomer contained in the polyester molding resin is bitten into the inside of the thermoplastic resin foam molding from the surface. The thermoplastic resin foam molding is polymerized and cured to obtain a coated molded product in which the thermoplastic resin foam molded product and the polyester are firmly fused. This is because the vinyl aromatic monomer polymer that forms the thermoplastic resin foam is swollen by the vinyl monomer in the polyester molding resin, and some of it is dissolved. It is presumed that the monomer permeates into the inside of the foam molded article. However, even if the vinyl aromatic monomer polymer is dissolved, the shape of the foamed molded article does not change or it disintegrates. This is because the thermoplastic resin foam molded article of the present invention has a vinyl aromatic monomer infiltrated into the polypropylene resin particles and undergoes graft polymerization and crosslinking polymerization, and has strong resistance to solvents, and has a small vinyl aromatic polymer portion. This is because it only swells. Furthermore, even if the molded product is partially dissolved, the shape of the molded product is retained by the outer surface of the polyolefin resin particles, so that the molded product will not be deformed or disintegrated. In a foamed molded product made by physically mixing a polypropylene resin and a vinyl aromatic monomer, the vinyl aromatic monomer is dissolved by the solvent of the polyester molding resin, causing the foamed molded product to deform and maintain its shape. unable to
It is unsuitable as a core material in polyester resin coatings.

The thermoplastic resin foam molded article in the method of the present invention is obtained by infiltrating the vinyl aromatic monomer into the polypropylene resin particles and foaming the graft polymer and crosslinked thermoplastic resin particles as described above. Like polystyrene foam, it is rigid, has good shape retention, is lightweight, and has extremely good engraving workability. Furthermore, since it is not attacked by the solvent of the polyester molding resin, it is easy to coat the polyester resin without losing its shape.The core material made of a thermoplastic resin foam molding and the polyester resin are firmly fused together. A molded body is obtained. The thickness of the polyester resin coating can be freely adjusted by repeating coating as necessary. It varies depending on the type and size of the molded object, but generally a few mm to 10-odd mm.
A tough coated molded product can be obtained with a thickness of .

The polyester resin-coated molded product obtained by the method of the present invention uses a thermoplastic resin foamed molded product as the core material, so it is extremely lightweight, and the polyester resin layer is extremely strong, so it can be used as a ship material, float, etc. Various tank construction materials, construction materials,
It can also be used for various other purposes.

Next, examples of the method of the present invention will be shown.

Example 1 40 parts of polypropylene (MI value 8.0) made into a pellet with a diameter of 1 mm to 3 mm by an extruder was mixed with 150 parts of water.
Metathesis method Disperse in a system of 0.2 parts of magnesium pyrophosphate and 0.02 parts of sodium dodecylbenzenesulfonate, and while maintaining the system at 85°C, add 60 parts of styrene monomer, 0.3 parts of benzoyl peroxide, and 1.0 parts of dicumyl peroxide. A mixed solution containing 1.0 parts of polybutadiene and 1.0 parts of 1,2-polybutadiene was dropped over a period of 7 hours, and after the dropwise addition was completed, the reaction was further carried out at 140°C for 4 hours, and then cooled to obtain polymer particles.

Next, 100 parts of the polymer particles, 100 parts of water, and 0.02 part of sodium dodecylbenzenesulfonate were charged into a pressure-resistant container, 20 parts of butane was pressurized, and the container was maintained at 80° C. for 6 hours. Thereafter, the mixture was cooled to 30° C. and then dehydrated and dried to obtain expandable thermoplastic resin particles. After pre-foaming this, it was filled into a mold and water vapor of about 5 kg/cm ² (gauge pressure) was introduced, and then cooled and taken out from the mold to obtain a foamed molded product.

Production of polyester resin-coated molded article 1000 g of liquid polyester molded resin obtained by adding styrene to the polycondensation resin obtained by mixing 98 g of maleic anhydride, 148 g of phthalic anhydride, 62 g of ethylene glycol, and 76 g of propylene glycol and causing a polycondensation reaction. Add about 400g of glass fiber to
Add a small amount of methyl ethyl kenton peroxide and cobalt naphthenate, and apply this repeatedly to the entire surface of the foamed molded product at room temperature to form a layer of about 3 mm.
A polyester resin layer having a thickness of . The surface of the obtained polyester resin coated molded product was firmly fused to the polyester resin, the polyester resin layer was extremely strong, and since the core material was foam, the coated molded product was lightweight. .

Example 2 40 parts of a random copolymer resin of polypropylene and polyethylene containing 1% polyethylene, made into a beret with a diameter of 1 mm to 3 mm using an extruder, 150 parts of water, and 0.2 parts of magnesium pyrophosphate by metathesis method
1 part, 0.02 part of sodium dodecylbenzenesulfonate, and while maintaining the system at 85°C, disperse 0.3 part of benzoyl peroxide in 60 parts of styrene monomer.
A mixed solution of dicumyl peroxide and a crosslinking aid was applied over a period of 7 hours, and after completion of the application, the reaction was further carried out at 140°C for 4 hours, and then cooled to obtain polymer particles. Next, this polymer particle 100
100 parts of water and 0.02 parts of sodium dodecylbenzenesulfonate were also charged into a pressure-resistant container, and 20 parts of butane was pressurized and maintained at 80°C for 6 hours. Thereafter, the mixture was cooled to 30°C, and then dehydrated and dried to obtain a foamable thermoplastic resin. This is heated with heated steam to form pre-expanded particles, which are then filled into a mold for approximately 3 kg/cm ²
(gauge pressure) water vapor was introduced, and after cooling, it was taken out from the mold to obtain a foamed molded product.

This foamed molded product was used as a core material and coated with polyester resin in the same manner as described in the production of a polyester resin-coated molded product in Example 1 to obtain a polyester resin-coated molded product.

Claims (1)

[Scope of Claims] 1 Polypropylene resin particles are reacted with a vinyl aromatic monomer to carry out graft polymerization and crosslinking polymerization, and a polybasic acid and polyvalent A method for producing a polyester resin-coated molded article, which comprises coating a polyester molding resin obtained by polycondensing alcohol with a vinyl monomer as a solvent and curing it. 2. The method for producing a polyester resin-coated molded article according to claim 1, wherein the polypropylene resin particles are polypropylene, a random copolymer of ethylene and propylene, or an ethylene-propylene-polyene copolymer. 3 The vinyl aromatic resin is styrene, α-methylstyrene, ethylstyrene, chlorostyrene,
A resin consisting of a polymer of bromostyrene, vinyltoluene, vinylxylene, isopropylxylene, or a mixture thereof, or a monomer copolymerizable with a vinyl aromatic monomer containing 50% by weight or more of these vinyl aromatic monomers. The method for producing a polyester resin-coated molded article according to claim 1, wherein the resin is a mixture of the following. 4 Thermoplastic resin, polypropylene resin 20
~80% by weight, vinyl aromatic resin 80-20% by weight
Claim 1, which is a thermoplastic resin consisting of
A method for producing a polyester resin-coated molded article as described in 2. 5. Production of a polyester resin-coated molded article according to claim 1, wherein the polybasic acid is maleic anhydride, fumaric acid, adipic acid, phthalic anhydride, isophthalic acid, tetrachlorophthalic anhydride, or a mixture thereof. Method. 6. Patents where the polyhydric alcohol is ethylene glycol, propylene glycol, 1,3-butylene glycol, diethylene glycol, dipropylene glycol, neopentyl glycol, bisphenol dioxyethyl ether, glycerin, pentaerythritol, mannitol, or a mixture thereof. A method for producing a polyester resin-coated molded article according to claim 1. 7 The vinyl monomer that is the solvent for the polycondensation resin is styrene, α-methylstyrene, vinyl acetate, methacrylate, diarylphthalate, chlorostyrene, vinyltoluene, divinylbenzene, acrylate, diallylbenzenephosphonate, N-vinylpyrrolidone. , maleimide,
The method for producing a polyester resin-coated molded article according to claim 1, which is triallyl cyanurate or triallyl phosphate. 8. A method for producing a polyester resin-coated molded article according to claim 1, which comprises using a polyester molding resin mixed with glass fiber.