JPH0512382B2 - - Google Patents

Description

[Detailed description of the invention]

"Industrial Application Field" The present invention relates to a synthetic resin molded product obtained by surface-treating a base material. More specifically, the present invention relates to synthetic resin molded products with excellent stain resistance and durability. ``Prior Art'' Conventionally, synthetic resins have been used in various fields, but they have had the disadvantage of being easily contaminated. For example, if a desk mat or document holder made of synthetic resin is used to hold documents copied using an electrostatic copying machine, thermal copying machine, etc., or if these documents are stored inside the desk mat, the printed side of the paper will be removed from the desk mat. When the printer comes into contact with the transparent cover of a document holder, printing ink transfers to the cover within a very short time, contaminating the cover, and furthermore, both sides of the document stick together, causing damage to the document. In particular, when the synthetic resin is a soft vinyl chloride resin, the above phenomenon is noticeable because the plasticizer bleeds out onto the surface of the molded product. In addition, when a molded product made of vinyl chloride resin comes into contact with a molded product made of other resins, such as ABS resin or styrene resin, there is a problem that the plasticizer migrates and contaminates the other resin molded products with which it comes into contact. . As a method to solve these problems, a method has been proposed in which the surface of a synthetic resin molded product containing vinyl chloride resin is destroyed with a specific resin or paint. For example, JP-A-56-74156 proposes a method of coating an epoxy resin coating composition on the surface of a synthetic resin molded article to form a film. Also, Japanese Patent Application Publication No. 1983-
Publication No. 57954, Japanese Patent Application Publication No. 59-176330, Japanese Patent Publication No. 59-176330,
No. 59-38105 proposes a method for forming a film from a fluororesin-based coating composition, and JP-A-59-105057 proposes a method for forming a film from a silicone resin-based coating composition. However, since the coating formed on the surface of the molded product according to the improved method described above is mainly made of thermoplastic resin, it is difficult to completely suppress surface contamination when the ambient temperature is high during use. This was difficult, and problems still arose. Therefore, in order to further improve the above-mentioned drawbacks, JP-A-59-12701 proposes a method of forming a crosslinked acrylic rubber layer on the surface. Further, Japanese Patent Publication No. 57-57485 proposes a method of forming a film of a cured silicone resin on a surface under light irradiation. However, the coatings obtained by these methods are hard and brittle, and cannot follow the deformation of the molded product that is the base material, causing cracks in the coating and peeling and detachment over time, resulting in long-term stable durability. There was a problem that the staining effect could not be sufficiently exhibited. "Problems to be Solved by the Invention" The present inventors have aimed to solve the above-mentioned conventional drawbacks and provide a synthetic resin molded product that effectively prevents contamination on the surface of the molded product. As a result of intensive study, the present invention has been completed. "Means for Solving the Problems" The gist of the present invention is to provide a silane polymer [A] having a hydrolyzable group directly bonded to a silicon atom and an alkyl ester of acrylic acid or methacrylic acid on the surface of a synthetic resin base material. (hereinafter referred to as (meth)acrylic acid alkyl esters),
Or [A] versus [B] of acrylic resin [B] obtained by polymerizing a mixture of this and an alkenylbenzene monomer and a copolymerizable α,β-ethylenically unsaturated monomer. ] is applied in a weight ratio of 20:1 to 1:15, and the mixture is applied at a temperature of 50 to 200℃.
It consists of a synthetic resin molded article formed by heating for 60 seconds to 60 minutes to form a film in which [A] and [B] are chemically bonded. The present invention will be explained in detail below. The synthetic resin in the present invention is not particularly limited, and may be selected from thermoplastic resins and thermosetting resins. For example, low density polyethylene, high density polyethylene, linear low density polyethylene, polypropylene, polyvinyl alcohol, polyvinylidene chloride, saturated polyester, methacrylic resin,
AS resin, ABS resin, nylon resin, polyacetal, polycarbonate, polyacrylate, polyvinyl acetate, ethylene-vinyl acetate resin, polyphenylene oxide, polysulfone, polyphenylene sulfide, fluorine resin, phenolic resin, urea resin, Examples include unsaturated polyester resin, epoxy resin, melamine resin, diallyl phthalate resin, silicone resin, polyimide resin, polyurethane FRP, and the like. Particularly when the synthetic resin is a vinyl chloride resin, the present invention is effective in preventing migration of plasticizers and the like to the surface and preventing contamination of the surface of the molded product. In the present invention, the vinyl chloride resin refers to polyvinyl chloride and a copolymer mainly composed of vinyl chloride. Monomers copolymerizable with vinyl chloride include vinyl esters, vinyl ethers, acrylic acid or methacrylic acid, and esters thereof, maleic acid or fumaric acid and esters thereof, maleic anhydride, aromatic vinyl compounds, Examples include halogenated vinylidene compounds, acrylonitrile, methacrylonitrile, ethylene, propylene, and the like. These monomers may be partially crosslinked by adding a trace amount of a compound containing a polyfunctional group. These vinyl chloride resins may be produced by any of conventionally known production methods such as emulsion polymerization, suspension polymerization, solution polymerization, and bulk polymerization. Note that vinyl chloride resin is a single resin (homopolymer) in terms of moldability and strength of molded products.
It can be used as a copolymer resin, or a combination of two or more resins. In order to impart flexibility to the vinyl chloride resin that serves as the base, 100 parts by weight of this resin is added.
20 parts by weight or more, preferably 30 to 100 parts by weight of plasticizer is blended. By adjusting the blending amount of plasticizer within the above range, the desired soft vinyl chloride molded product can be produced.
It can provide excellent flexibility and mechanical properties. Examples of the plasticizer include di-n-octyl phthalate, di-2-ethylhexyl phthalate,
Phthalate esters such as dibenzyl phthalate, butybenzyl phthalate, diisodecyl phthalate, didodecyl phthalate, diundecyl phthalate, dioctyl adipate, di-adipate
Aliphatic dibasic acid esters such as n-butyl and dibutyl sebacate; glycol esters such as pentaerythritol ester and diethylene glycol dibenzoate; fatty acid esters such as methyl acetyl ricinoleate; epoxidized soybean oil, epoxidized linseed oil, etc. Epoxidized oil; citric acid esters such as acetyl tributyl citrate, acetyl trioctyl citrate, and tri-n-butyl citrate; trialkyl trimellitate, tetra-n-octyl pyromellitate, polypropylene adipate, and other polyesters Examples include plasticizers and the like. These plasticizers may be one type or two.
You may use combinations of more than one species. In addition to the plasticizer, the vinyl chloride resin may contain, if necessary, known resin additives that are usually added to synthetic resins for molding, such as heat stabilizers, antioxidants, lubricants, and thickeners. Agents, antistatic agents, surfactants, ultraviolet absorbers, light stabilizers, pigments, dyes, etc. can be blended. However, including plasticizers,
In order to formulate a vinyl chloride resin compound composition for molding by blending other known resin additives, ordinary blending and mixing techniques such as a ribbon blender, Banbury mixer, super mixer and other compounding machines and mixers are used. A method can be adopted. There are no particular limitations on the shape of the synthetic resin molded article of the present invention by molding the vinyl chloride resin blended composition. However, from the viewpoint of ease of the process of forming a coating, a sheet, film, plate, or tubular form is suitable. These molding methods are commonly used. For example, a calender molding method, an extrusion molding method, an inflation molding method, an injection molding method, a casting method, etc. may be employed as appropriate. In the present invention, raw material monomers for the silane polymer having a hydrolyzable group directly bonded to a silicon atom include, for example, aminomethyltriethoxysilane,
Aminoalkylalkoxysilanes such as N-β-aminoethylaminomethyltrimethoxysilane, γ-aminopropyltrimethoxysilane, N-(trimethoxysilylpropyl)-ethylenediamine, N-(dimethoxymethylsilylpropyl)-ethylenediamine; γ- Glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, β
- Epoxyalkylalkoxysilanes such as (3,4-epoxycyclohexyl)ethylmethyldimethoxysilane; mercaptoalkylalkoxysilanes such as γ-mercaptopropyltrimethoxysilane, γ-mercaptopropylmethyldimethoxysilane; tetramethoxysilane, tetraethoxysilane, Tetrabutoxysilane, trimethoxyneopentoxysilane, dimethoxydiethoxysilane, trimethoxy-n-propoxysilane,
Dimethoxydineopentoxysilane, bis(2-
Tetraalkoxysilanes such as (ethylhexoxy) diethoxysilane; Alkyltrialkoxysilanes such as methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane; Dialkyldialkoxysilanes such as dimethyldimethoxysilane, dimethyldiethoxysilane Silane; halogenated alkylalkoxysilane such as γ-chloropropyltrimethoxysilane, 3,3,3-trichloropropyltrimethoxysilane; alkylacyloxysilane such as methyltriacetoxysilane, dimethyldiacetoxysilane; trimethoxysilane, trimethoxysilane; Hydrosilane compounds such as ethoxysilane; vinyltrimethoxysilane, vinylethoxysilane,
vinyltris(β-methoxyethoxy)silane,
Allyltriethoxysilane, γ-(meth)acryloxypropyltrimethoxysilane, γ-(meth)
Acryloxypropyltriethoxysilane, γ-
Examples include unsaturated group-containing silane compounds such as (meth)acryloxypropylmethyldimethoxysilane. The silane polymer [A] can be obtained by hydrolyzing and condensing these silane compound monomers. Hydrolysis is carried out, for example, by adding water in the presence of an acid or alkali catalyst in a combined alcohol system. At this time, if more than an equivalent amount of water is added to the hydrolyzable group, it will completely decompose and become alcoholic silica gel or silica sol, or a siloxane-based composite, so the amount of water added must be less than the equivalent amount. . Among silane polymers, especially those with the general formula (R ¹ , O) ₃ Si
[OSi(OR ² ) ₂ ] _o (OR ³ ) (wherein R ¹ to R ³ are each,
They represent the same or different alkyl groups, aryl groups, alkylaryl groups, arylalkyl groups, aryloxyalkyl groups or alkyloxyalkyl groups, and n represents a positive integer. ) is preferred. Among these, compounds in which R ¹ to ^{R 3} are each the same or different alkyl groups having 4 or less carbon atoms are particularly preferred. These silane compounds may be used alone or in combination of two or more. The acrylic resin in the present invention refers to an alkyl ester of acrylic acid or methacrylic acid (hereinafter referred to as (meth)acrylic acid alkyl ester) monomer alone or a mixture of this and an alkenylbenzene monomer. , and copolymerizable α,
It is obtained by polymerizing a β-ethylenically unsaturated monomer under normal polymerization conditions. Examples of the (meth)acrylic acid alkyl esters used in the present invention include acrylic acid methyl ester, acrylic acid ethyl ester, acrylic acid n-propyl ester, acrylic acid isopropyl ester, acrylic acid n-butyl ester, and acrylic acid methyl ester. -2-ethylhexyl ester,
Examples include decyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, 2-ethylhexyl methacrylate, and decyl methacrylate. Generally, acrylic acid alkyl esters having an alkyl group having 1 to 20 carbon atoms and/or methacrylic acid alkyl esters having an alkyl group having 1 to 20 carbon atoms are used. Examples of the alkenylbenzenes used in the present invention include styrene, α-methylstyrene, and vinyltoluene. Such alkenylbenzenes and (meth)
When using a monomer mixture with acrylic acid alkyl esters, it usually depends on the amount of α,β-ethylenically unsaturated monomer used (meth).
The proportion of the acrylic acid alkyl ester used is preferably 10% by weight or more. Examples of other copolymerizable α,β-ethylenically unsaturated monomers used to obtain the acrylic resin of the present invention include acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, and crotonic acid. α, β-ethylenically unsaturated carboxylic acids such as , itaconic acid; α, β-ethylenically unsaturated sulfonic acids such as ethylene sulfonic acid; 2-acrylamido-2-methylpropanoic acid; α, β-
Examples include ethylenically unsaturated phosphonic acids; acrylamides; amino esters of acrylic acid or methacrylic acid; glycidyl esters of acrylic acid or methacrylic acid; acrylic acid or methacrylates. Even if these monomers are used alone,
Alternatively, two or more types may be used in combination. Examples of the polymerization initiator used in producing the acrylic resin of the present invention include persulfates such as ammonium persulfate and potassium persulfate; organic peroxides such as acetyl peroxide and benzoyl peroxide. These are used in an amount of 0.1 to 10% by weight based on the total amount of monomers charged. Acrylic resin can be produced using bulk polymerization method, solution polymerization method,
It can be produced by any polymerization method such as suspension polymerization or emulsion polymerization. The obtained acrylic resin can be further used by adding compounds such as vinyl chloride/vinyl acetate resin, vinyl chloride resin, cellulose ether, and the like. The mixing ratio of the silane polymer [A] and the acrylic resin [B] is preferably such that the weight ratio of [A] to [B] is in the range of 20:1 to 1:15. When the proportion of the silane polymer [A] is above the above range,
The coating formed on the molded product becomes brittle and has poor adhesion to the base material, making it easy to peel off, which is undesirable.Also, if the proportion of acrylic resin [B] exceeds the above range, the stain resistance will deteriorate. This is not preferable because the effect of this method is not particularly pronounced. Among the above ranges, it is particularly preferable that [A] to [B] be in the range of 15:1 to 1:10. A liquid dispersion medium may be further added to the above composition as required. Such liquid dispersion media include monohydric alcohols such as methyl alcohol, ethyl alcohol, and isopropyl alcohol; polyhydric alcohols such as ethylene glycol, diethylene glycol, and glycerin; cyclic alcohols such as dibenzyl alcohol; and cellosolve acetates. ; Examples include ketones. These liquid dispersion media may be used alone or in combination, but consideration should be given to the dispersion stability of the coating composition, wettability to the surface of the molded product when using the coating method, difficulty in removing the liquid dispersion medium, and economic efficiency. It is preferable to decide by The above coating composition may further contain small amounts of acids or alkalis, antifoaming agents, surfactants, lubricants,
Mix conventional additives such as antistatic agents, antioxidants, ultraviolet absorbers, light stabilizers, film-forming aids, thickeners, pigments, pigment dispersants, fungicides, algaecides, and inorganic fillers. be able to. When applying the above-mentioned coating composition to the surface of a synthetic resin base material, roll coating method, dip coating method,
Brush coating method, spray coating method, bar coating method,
Any method known per se such as a knife coating method may be used. When the coating composition is formed as a single film without being in a solution state, a coextrusion method, an extrusion coating method, an extrusion lamination method, and a lamination method are used. A film derived from the above coating composition is formed on the surface of a synthetic resin substrate under heat treatment. As a result, the silane compound and the acrylic resin are chemically bonded, and the coating becomes strong and has excellent barrier properties against contaminants, improving stain resistance. Heat treatment methods when using a coating method as a coating method include, for example, hot air heating, infrared heating, far infrared heating, etc. However, in consideration of heat treatment efficiency and safety, hot air heating is advantageous. In this case, the temperature condition is in the range of 50 to 200℃,
It is best to choose a time between 10 seconds and 60 minutes. The amount of solid matter adhered to the film formed on the surface of the synthetic resin base material under heat treatment is 0.05 to 20 g/m ² ,
It is preferably in the range of 0.1 to 10 g/m ² . If the adhesion between the surface of the base material and the coating is insufficient, the surface of the base material may be subjected to plasma treatment or corona discharge treatment before applying the above-mentioned coating composition. It is better to modify the surface. There are no particular limitations on the shape of the synthetic resin molded article of the present invention. However, from the viewpoint of ease of the process of forming a coating, a sheet, film, plate, or tubular form is suitable. These molding methods are appropriately selected from commonly used methods such as calendar molding, extrusion molding, inflation molding, injection molding, and casting. "Effects of the Invention" and "Operations" The synthetic resin molded article according to the present invention has a specific coating formed on its surface, and this coating has an extremely excellent effect of preventing pollutants.
Therefore, the synthetic resin molded product of the present invention can maintain a beautiful external appearance for a long time, and is particularly suitable for desk mats,
It is useful in a variety of fields such as medical record holders and document holders for stationery, where electrostatically copied paper and thermally copied paper are sandwiched or inserted, and its industrial value is great. In addition, especially when the synthetic resin is a soft vinyl chloride resin containing a large amount of plasticizer, bleed-out of the plasticizer, etc. on the surface of the molded product is suppressed, resulting in a molded product with significantly improved stain resistance. This will greatly expand the field of use of resin. "Examples" Hereinafter, the present invention will be explained in detail based on Examples, but the present invention is not limited to the following examples unless it exceeds the gist thereof. Examples 1 to 4, Comparative Examples 1 to 2 (1) Preparation of acrylic resin Manufacturing examples 1 to 4 100 parts by weight of isopropyl alcohol was placed in a reactor equipped with a thermometer, a stirrer, a reflux condenser, and a nozzle for adding raw materials. , 1.0 part by weight of benzoyl peroxide and 100 parts by weight of the mixture of each monomer shown in Table 1 were charged, and while stirring in a nitrogen gas stream, the mixture was heated at 80°C for 3 hours, and then 0.5 part by weight of benzoyl peroxide was added. The reaction was continued at the same temperature for about 3 hours to obtain acrylic resins A to D. (2) Preparation of coating compositions The products obtained in the above production examples (acrylic resins A to D) were blended with silane polymer [A] of the type and amount shown in Table 2 to produce various coating compositions. I prepared something. (3) Formation of coating After drying the obtained coating composition with isopropyl alcohol, the coating amount (as solid content) is 3.0 g/m ²
It was diluted to give the following properties and applied to the surfaces of various resin films by bar coating as shown in Table 2. Then, it was allowed to stay in hot air at 100°C for 3 minutes to scatter the solvent and perform heat treatment at the same time. However, in Comparative Example 2, after applying the coating composition,
The solvent was scattered by air drying without overheating to obtain a dry film. (4) Evaluation of coating The properties of the coating formed on the obtained film were evaluated using the methods described below. Adhesion Cellophane tape is adhered to the coated surface of each film, and when this cellophane tape is peeled off,
The state of peeling of the film was observed with the naked eye. The results are shown in Table 2. The evaluation criteria are as follows. 〇…The coating did not peel off at all and remained completely. 〇×: 2/3 or more of the coating remained without being peeled off. △...2/3 or more of the coating was peeled off. ×...The film was completely peeled off. Contamination resistance Each contaminant is attached to the coating surface of the film,
After leaving it at room temperature for 48 hours, the contaminants were wiped off with absorbent cotton and the traces were observed. The results are shown in Table 2. The evaluation criteria are as follows. ◎…No traces found at all. 〇… Traces are observed on a part of the film. △... Traces are observed on 2/3 or more of the coating. ×... Traces are observed on the entire surface of the coating. Stain Resistance Each film was cut into 10 cm x 10 cm squares, and the printed surface of electrostatic copying paper or thermal copying paper was brought into close contact with the surface on which the film was formed (one surface was used for the comparative example film). In this state, apply a load of 2 kg and heat at 50°C.
It was left in the oven for 48 hours. The film was then removed from the oven, the load was removed, each copy paper was peeled off, and the degree of contamination on the film surface was observed. The results are shown in Table 2. The evaluation criteria are as follows. ◎…No traces found at all. 〇… Traces are observed on a part of the film. △... Traces are observed on 2/3 or more of the coating. ×... Traces are observed on the entire surface of the coating.

【table】

【table】

[Table] *1 Formed content *2 Film-formed product under natural drying conditions From Table 2, the synthetic resin molded product according to the present invention is as follows:
In particular, it has excellent stain resistance, so it can prevent contamination, dust, dirt, etc. from adhering to the surface of the molded product.
It can be seen that a beautiful appearance can be maintained for a long period of time. Examples 5 to 8, Comparative Examples 3 to 4 Next, Examples and Comparative Examples in which the synthetic resin is a vinyl chloride resin will be shown. (1) Preparation of base film Polyvinyl chloride (=1400) 100 parts by weight dioctyl phthalate 50 〃 Epoxidized soybean oil 3 〃 Barium-zinc composite liquid stabilizer 1.5 〃 Barium stearate 0.2 〃 Zinc stearate 0.4 〃 Resin consisting of A composition was prepared, mixed for 10 minutes using a super mixer, and then kneaded on a mill roll heated to 180°C to prepare a soft vinyl chloride resin film with a thickness of 0.3 mm. (2) Formation of a film A silane polymer of the type and amount shown in Table 3 and an acrylic resin are blended, and isopropyl alcohol is added thereto so that the solid content is 20% by weight.
A coating composition was obtained. On one side of the base film prepared by the above method,
The above coating composition was applied using a #5 bar coater,
Each was applied. The coated film was kept in an oven at 130° C. for 3 minutes to volatilize the solvent and at the same time heat-treated. However, in Comparative Example 5, after applying the coating composition, the solvent was evaporated by natural drying without heat treatment to obtain a dry coating. The amount of coating on each film obtained was approximately 2.0 g/m ² . (3) Evaluation of film Adhesion was evaluated in the same manner as in Examples 1 to 4, and stain resistance was evaluated in the same manner as in Examples 1 to 6. Furthermore, a plasticizer migration test was conducted in the following manner. Each of the 11 types of films was cut into 10 cm x 10 cm squares, and a 0.5 mm thick polystyrene sheet was adhered to the surface on which the film was formed (one surface for the film of Comparative Example 6). In this state, a load of 2 kg was applied and the product was left in an oven maintained at 50° C. for 48 hours. The film was then removed from the oven, the load was removed, the polystyrene sheet was peeled off, and the weight loss of each of the 11 types of films was measured. The lower the value, the less the plasticizer migrates from the film surface. The evaluation results are shown in Table 3.

[Table] *1 Formed content *2 Film-formed product under air-drying conditions From Table 3, it is clear that the vinyl chloride resin molded product according to the present invention has particularly excellent plasticizer migration resistance and stain resistance, so it is a molded product. It can be seen that it is possible to prevent contamination, dust, dirt, etc. from adhering to the surface of the product, and to maintain a beautiful appearance for a long period of time.

Claims (1)

[Scope of Claims] 1 A silane polymer [A] having a hydrolyzable group directly bonded to a silicon atom on the surface of a synthetic resin base material and an alkyl ester of acrylic acid or methacrylic acid (hereinafter referred to as (meth)acrylic acid) (referred to as acid alkyl esters), or a mixture of this and an alkenylbenzene monomer, and a copolymerizable α,β-ethylenically unsaturated monomer. [A] of acrylic resin [B]
A mixture of [B] in a weight ratio of 20:1 to 1:15 is applied and heated at a temperature of 50 to 200°C for 10 seconds to 60 minutes to chemically bond [A] and [B]. A synthetic resin molded product formed with a coated film. 2. The synthetic resin molded product according to claim 1, wherein the synthetic resin base material is made of a vinyl chloride resin containing 20 parts by weight or more of a plasticizer per 100 parts by weight of the vinyl chloride resin. . 3 The silane polymer [A] has the general formula (R ¹ O) ₃ Si[OSi(OR ² ) ₂ ] _o (OR ³ ) (wherein R ¹ to R ³ are each the same or different alkyl group , an aryl group, an alkylaryl group, an aryloxyalkyl group, or an alkyloxyalkyl group, and n represents a positive integer. Synthetic resin molded product according to item 2.