JP2529568B2 - Resin molded product - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a molded product of a plastisol composition, and more specifically, to easily manufacture various molded products having excellent surface hardness, matting and dry touch properties. It relates to a resin molded product obtained by using the obtainable plastisol composition.

(Prior Art) Plastisol is used in various applications because it can be shaped into a liquid and heated to obtain a wide variety of molded products of any shape and from hard to soft. For example, cushion floors, wallpapers, anticorrosive paints, precoated steel sheets, gloves, boots, leather, toys, films, adhesives, coated products, and the like.

The chemical structure and amount of the plasticizer have a great influence on the hardness and feel of the product, but since they serve as a dispersion medium for the vinyl chloride polymer particles in sol processing, they also have a decisive effect on processability. As a matter of course, when the amount of the plasticizer is large, a sol having a low viscosity is given to facilitate processing. On the other hand, when obtaining a hard product, the plasticizer is reduced and the workability deteriorates. It is often pointed out that the soft vinyl chloride resin has a sticky surface feel and has a reduced commercial value depending on the application. Various methods have been tried so far as methods for increasing hardness and eliminating stickiness on the surface.

The method of reducing the amount of the plasticizer increases the viscosity of the sol, making it difficult to process. The method of using a reactive plasticizer such as (meth) acrylic acid ester or diallyl phthalate as a part of the plasticizer requires a peroxide catalyst at the time of compounding. There are problems that the decomposition is promoted, the reactive plasticizer starts polymerization during storage of the sol, and the viscosity increases. The method of reducing the plasticizer and replacing a part of the polyvinyl chloride paste resin with a vinyl chloride resin having a large particle size has a limit to the plasticizer weight reduction. Since it swells and softens, there is a limit to increasing hardness and preventing stickiness. Also, the method of adding an inorganic substance is effective in increasing hardness and improving stickiness, but it increases the viscosity of the sol, deteriorates processability, and significantly reduces product strength. Furthermore, the method of surface-treating the product surface with an acrylic polymer or polyurethane is economically disadvantageous due to the additional steps.

(Problems to be Solved by the Invention) The present inventor uses a specific methacrylate resin and a plasticizer in a plastisol composition to enhance the hardness of the product without improving the workability and to easily improve the stickiness. I found what I could do.

(Means for Solving the Problem) That is, according to the present invention, a resin for polyvinyl chloride paste, b. A methacrylate resin and c. A plasticizer are contained, and b is 90% by weight or more of methyl methacrylate. It is a homopolymer or a copolymer containing a powdery polymer having an average molecular weight of 100,000 or more and an average particle diameter of 1 to 200μ, and a / b is 20/80 to 80/20 in weight ratio. There is provided a resin molded article (excluding steel sheet coating) obtained by shaping the plastisol composition which is, and heating and gelling.

The polyvinyl chloride paste resin used in the present invention may be any one that is produced by emulsion polymerization or emulsion suspension polymerization and is dispersed in a plasticizer to form a sol. A copolymer of vinyl and vinyl acetate, vinyl propionate, vinylidene chloride, acrylic acid ester, methacrylic acid ester or the like is used alone or in combination with a vinyl chloride homopolymer. Most of the paste resins have an average particle size of 0.1 to 2 μ, but a part of the paste resin can be replaced with a vinyl chloride resin having an average particle size of 10 to 200 μ.

As the methacrylate resin, a homopolymer containing 90% by weight or more of methyl methacrylate or a copolymer of methyl methacrylate and another monomer copolymerizable therewith is used. Examples of other monomers include acrylic acid, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, cyclohexyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, ethoxyethyl acrylate, butoxyethyl acrylate, hydroxyethyl acrylate, hydroxypropyl. Acrylate, dimethylaminoethyl acrylate, glycidyl acrylate, allyl acrylate, (poly) alkylene glycol acrylate, trimethylolpropane triacrylate, acrylic acid metal salt and other acrylates; methacrylic acid, ethyl methacrylate, propyl methacrylate, butyl methacrylate, octyl methacrylate, lauryl Methacrylate, stearyl methacrylate Methacrylate such as methoxyethylmethacrylate, butoxyethylmethacrylate, hydroxyethylmethacrylate, hydroxypropylmethacrylate, dimethylaminoethylmethacrylate, glycidylmethacrylate, allylmethacrylate, (poly) alkyleneglycoldimethacrylate, trimethylolpropanetrimethacrylate; ethylene, propylene, etc. Olefins; butadiene, isoprene and other dienes; vinyl chloride, vinylidene chloride and other halogenated vinyls; vinyl acetate, vinyl propionate and other vinyl esters; allyl vinyl ether and other vinyl ethers; styrene, chlorostyrene, and other styrene derivatives. . When the content of methacrylate is less than 90% by weight, Tg is lowered and it is difficult to obtain the desired feel. It is necessary that the average molecular weight of the methacrylate resin is 100,000 or more (the average molecular weight here is measured by liquid chromatography. It means the weight average molecular weight. The same applies hereinafter.) If less than 100,000, matte The effect is insufficient. It is preferable that the degree of polymerization is high, and a cross-linked polymer insoluble in a solvent may be used. If the average molecular weight is 100,000 or more, it is effective in hardness and matting, but 1,000,000 or more,
Alternatively, if it is a cross-linked polymer, a higher effect can be obtained.
The methacrylate resin should have an average particle size of 1μ to 200μ. If it is less than 1μ, the matting effect is insufficient.
If it exceeds 200μ, the appearance of the product is impaired. If the particle size is large, the matting effect and the dry touch property are not necessarily improved, but different effects are produced depending on the particle size. Relatively small particle sizes give a velvety surface and relatively large particle sizes give a rough product. Both are matte and have excellent dry touch. The methacrylate resin (b) is used as a mixture with the polyvinyl chloride paste resin (a), but the weight ratio of the resin needs to be a / b = 20/80 to 80/20. When a / b is less than 20/80, the strength of the molded product is poor and the value as a product is reduced. If it exceeds 80/20, the matte effect and dry touch effect will be insufficient.

The plasticizer may be any as long as it is generally used for vinyl chloride resins, and examples thereof include phthalic acid such as dibutyl phthalate, butylbenzyl phthalate, di-2-ethylhexyl phthalate, diisononyl phthalate, mixed alkyl phthalate and diisodecyl phthalate. Polyester plasticizer, dioctyl, which is a condensate of phosphate ester such as ester, tricresyl phosphate and trioctyl phosphate, dibasic acid such as adipic acid and phthalic acid and dihydric alcohol such as ethylene glycol and propylene glycol. Adipates, dioctyl azelates, dialkyl fatty acid esters such as dibutyl sebacate, chlorinated paraffins and epoxidized vegetable oils can be used. The plasticizer swells the vinyl chloride resin at high temperature, softens and dissolves the particles, homogenizes and forms a uniform film.

The object of the present invention is to improve hardness, deluster, and improve dry touch property to give micro unevenness to the product surface,
It is considered to be achieved by a mechanism such as containing hard particles in the system and forming an unplasticized resin layer on the surface, but it is inconsistent with the above mechanism in which the plasticizer dissolves the resin. However, the plastisol composition used in the present invention solves this contradiction. That is, the methacrylate resin has a slower absorption rate of the plasticizer than the polyvinyl chloride, but has a low absorption capacity, and the melt viscosity is very high even when the plasticizer is absorbed, so the polyvinyl chloride is heated and melted. However, since the methacrylate resin does not melt and flow easily, the surface tension does not smooth the surface and the uneven shape is likely to remain. Further, there are few plasticizers inside the methacrylate resin exposed on the surface and there are few substances that cause stickiness. Further, the methacrylate resin is less plasticized and has a high hardness even when cooled to room temperature. It is considered that hardness and surface dry touch are improved by such a mechanism. As a methacrylate resin,
The higher the average degree of polymerization and the higher the methyl methacrylate component, the more difficult it is to melt and flow, and the greater the effect.

In addition, since the methacrylate resin has compatibility with polyvinyl chloride, the polymer at the particle interface becomes homogeneously compatible after melt molding, and as a result, mechanical and physical properties are not impaired. It is possible to obtain strong products. In addition, transparency, heat stability, and light stability are better than those of polyvinyl chloride, so that those properties are improved.

As the other compounding agent, any compound used for processing polyvinyl chloride paste can be used. For example, reactive plasticizer, cross-linking agent, filler, heat stabilizer, light stabilizer, ultraviolet absorber, epoxy compound, diluent, flame retardant,
A foaming agent, a hygroscopic agent, an adhesive, a pigment, a viscosity reducing agent, an antifoaming agent, a release agent, etc. can be used according to a conventional method.

Next, a method of forming into a sol, shaping, and molding will be described, but the method does not limit the content of the present invention,
Any method is possible. As a method for producing a sol, the compounding ingredients such as a polyvinyl chloride pace resin, a methacrylate resin, and a plasticizer are uniformly kneaded with a conventional mixer to obtain a uniform dispersion. Examples of the mixer include a planetary mixer, a kneader, a three-roll mill, a Hobart mixer, a butterfly mixer, a dissolver, a raider, a ribbon blender, and a Henshur mixer. The mixed and homogenized sol is used with or without defoaming. Defoaming methods include vacuum defoaming and vibration defoaming. The prepared sol can be shaped into an arbitrary shape by a processing machine.
For example, a doctor knife, a reverse roll, a natural roll, a floating knife, an air knife, a curtain flow, etc. can be spread-coated on the base material. Further, it can be applied to the entire surface or a part of the base material by a screen, an intaglio roll, a gravure roll, a spray or the like. It can be shaped into an arbitrary shape by slush molding, dip molding, rotational molding, casting, or the like. The shaped sol gels and melts only by heating, and when cooled, it becomes a tough molded product. The heating and melting conditions are, for example, about 150 ° C to 300 ° C.
The conditions may be, for example, about 0.5 to about 10 minutes at ° C.

(Effects of the Invention) Thus, according to the present invention, it is possible to easily obtain a polyvinyl chloride molded product having excellent hardness, matting and dry touch properties as compared with the prior art. If it is applied to the surface layer of floor materials and wall materials, it will be a product with a micro-roughened surface and a dry finish. When applied as a coating material for coating the surface of metal or the like, a coating film having a dull and hard surface can be obtained. When applied to sheets and films, products with a dry-touch surface without stickiness can be obtained. When applied to table cloths and leather, products with non-sticky surfaces can be obtained, which prevent sticking and migration of plasticizers to other materials with which they come into contact. When applied to gloves and soaked products, it is easy to remove the mold and the product feels good. Not only the performance as a product that the surface of the molded product is non-adhesive is excellent, but also in the molding process and distribution process, for example, good mold release property, handleability, or wrinkle resistance, It also has the advantage that dust is unlikely to adhere.

(Examples) The present invention will be described in more detail with reference to the following examples. The parts and% in the examples and comparative examples are based on weight unless otherwise specified.

 The evaluation criteria are as follows.

Hardness: Hardness measured by Duro A hardness tester.

Matte: Gloss meter used, light reflectance at 60 ° reflection angle.

Dry touch property: The degree of stickiness when the surface of a molded product is touched with a finger is judged according to the following criteria.

◎ The surface is smooth and feels like paper. ○ There is no sticky feeling and it is close to the feeling of paper. △ There is a little sticky feeling. × There is no sticky finger, but there is sticky feeling. Viscosity: The sol after kneading and defoaming is 23 ℃ ± 2 ℃, relative humidity 50
% Viscosity measured with a B-type viscometer after being left in an atmosphere of ± 10% for 1 hour.

Moldability: Shaped by coating, etc., and performance of the molded product after heating and melting (thickness, uniformity, strength) is judged according to the following criteria.

◎ Good ○ Almost good △ Slightly problematic × Problematic × × Unmoldable Examples 1-5, Comparative Examples 1-5 Mixing the compounding compositions shown in Table-1 with an Ishikawa type raikai machine, vacuum defoaming machine Degassed at 5 mmHg for 5 minutes. The methacrylate resin having the composition, the degree of polymerization and the particle size shown in Table 2 was synthesized and used. The sol composition was applied on a glass plate to a thickness of 300 μ by a doctor blade, and then heat-molded in a hot air circulation oven at 200 ° C. for 5 minutes. Table 1 shows the results of evaluation and determination of the molded sheet by the method described above.

According to the present invention, it is possible to obtain a dry-touch molded article having good hardness and matting without impairing the moldability.

Example 6, Comparative Example 6 A sol having the composition shown in Table 3 was prepared in the same manner as in Examples 1 to 5, and cold dipping was performed using a glove-type mold to examine hardness and dry touch property. The results are shown in Table-3.
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Claims (1)

(57) [Claims] 1. A resin for polyvinyl chloride paste, b. A methacrylate resin, and c. A plasticizer, wherein b is a homopolymer or copolymer containing 90% by weight or more of methyl methacrylate, A powdery polymer having an average molecular weight of 100,000 or more and an average particle size of 1 to 200μ, wherein a / b is a weight ratio.
A resin molded product (excluding steel plate coating) obtained by shaping a plastisol composition of 20/80 to 80/20, heating and gelling.