JPH0126628B2 - - Google Patents

Description

[Detailed description of the invention]

(a) Purpose of the invention [Field of industrial application] The present invention relates to a paint for forming a leather tone coating film, and is used for coating covers of office machines, audio equipment, etc., and surfaces made of PVC leather in automobile interior parts. The present invention relates to a surface finishing paint that has excellent properties such as leather tone, flexibility, abrasion resistance, and adhesion. [Prior Art] Vinyl chloride resin moldings and ABS resin moldings are used for covers of office machines, audio equipment, etc., and interior materials for houses and automobiles. Especially recently, the surface is finished to have a leather-like appearance.
A so-called leather tone finish is carried out by calendering or the like, and then a polyurethane paint is further applied on the resulting leather surface. [Problems to be solved by the invention] With conventional polyurethane paints, it is not possible to finish the surface while maintaining a satisfactory tone, and since urethane paints are reactive paints, it takes a long time until the paint film is completely cured. It took approximately one week to dry, and the coating film was not sufficiently cured immediately after drying, and the coating film sometimes peeled off when subjected to a strong impact. Furthermore, it could not be said that the adhesion after curing was sufficiently satisfactory. In addition, there has been a recent demand for softer interior parts for automobiles, and softer materials such as soft PVC are being used.
When a molded product is surface-finished with a polyurethane paint, the coating film has insufficient flexibility and adhesion, resulting in wrinkles in the paint film when the molded product is bent. The present invention aims to provide a paint that solves the above problems. (B) Structure of the Invention [Means for Solving the Problems] The present inventors have completed the present invention as a result of repeated studies on the above-mentioned problems. That is, the present invention utilizes vinyl chloride monomer (hereinafter referred to as MVC).
) or a monomer mixture of vinyl chloride monomer and a monomer copolymerizable with vinyl chloride monomer (hereinafter referred to as MVC monomer), the above monomer or monomer Soluble in body mixtures with a softening point of 20~
A paint for forming a leather tone coating consisting of a thermoplastic resin obtained by polymerizing the above monomer or monomer mixture in the presence of 3 to 100 parts by weight of a thermoplastic polyurethane elastomer (hereinafter referred to as TPU) at 100 ° C. be. [Function] The thermoplastic resin used in the present invention is a combination of TPU and MVC.
Or in a state dissolved in MVC monomer, MVC or
It is obtained by polymerizing MVC monomers. Although the nature of this reaction is not clear,
It is presumed that a certain type of chemical bonding, ie, a reaction called so-called graft copolymerization, occurs between TPU and MVC or MVC-based monomers. Such urethane
By using vinyl chloride copolymer resin,
It has improved laser tone and adhesion, and since it is a soft resin paint that does not require curing, it also has improved drying properties and flexibility. [TPU] TPU in the present invention is one that is substantially soluble in MVC or MVC monomer under the polymerization conditions of the present invention, and has a softening point of 20 to 100.
℃, preferably 30 to 60℃. If the softening point exceeds 100°C, it will be difficult to dissolve in MVC or MVC-based monomers, and if it has a softening point below 20°C, the resulting polymer will have poor tensile strength and heat resistance. Generally, TPU refers to an elastomer having urethane bonds in the molecule, and has a linear block copolymer structure of polyurethane as a soft segment and polyurethane as a hard segment. Generally, soft segments are obtained by reacting a polymer diol having hydroxyl groups at both ends with a diisocyanate, and hard segments are obtained by reacting a glycol or diamine with a diisocyanate. The TPU used in the present invention is soluble in MVC or MVC monomers and has a softening point in the range of 20 to 100°C, and in order to have such physical properties, the selection of soft segments and hard segments is necessary. It becomes necessary. If there are too many hard segments and the molecular weight becomes large, solubility will be poor and the softening point of TPU will be 100%.
℃, it is necessary to limit the amount of hard segments used. Therefore, used in the present invention
A TPU consists mostly of soft segments and can contain a small amount of hard segments if necessary. Polyester diols, polyether diols, polyolefin diols, polylactone diols, and the like having a number average molecular weight of 500 to 10,000 are used as the polymer diol constituting the soft segment of TPU. Examples of polyester diols include glutaric acid, adipic acid, succinic acid, suberic acid, sebacic acid, oxalic acid, methyladipic acid, pimelic acid, azelaic acid, phthalic acid, terephthalic acid, isophthalic acid, maleic acid, and fumaric acid. Those obtained by an esterification reaction between a basic acid and a diol such as ethylene glycol, 1,4-butanediol, 1,6-hexanediol, propylene glycol, diethylene glycol, or neopentyl glycol are used. As the polyether diol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, etc. are used. As the polyolefin diol, polybutadiene diol and the like are used, and as the polylactone diol, polycaprolactone diol and the like are used. In the present invention, in order for the thermoplastic resin to have excellent performance, TPU using polyester diol, especially adipic acid-based polyester diol, is required.
is preferred. As the glycols and diamines constituting the hard segment of TPU, the diols shown as the raw materials for polyester diols and aliphatic and aromatic diamines such as ethylene diamine, propylene diamine, and xylene diamine are used. The diisocyanates that make up the soft segment and hard segment of TPU include 4,
4'-diphenylmethane diisocyanate, 4,
4'-diphenyl diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,5-naphthalene diisocyanate, xylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, hexamethylene diisocyanate, isof Oron diisocyanate, etc. may be used alone or in combination of two or more. A suitable type of TPU used in the present invention
Examples include Pandex T-5265 (trade name, manufactured by Dainippon Ink and Chemicals) (polyurethane mainly composed of adipic acid-based polyester diol and aliphatic diisocyanate; softening point, 53°C; weight average molecular weight, 120,000), Pandex T-525 (trade name: Softening point, 47
℃) etc. The amount of TPU used is 3 to 100 parts by weight, preferably 5 to 60 parts by weight, based on 100 parts by weight of MVC or MVC monomer at the time of preparation. For 100 parts by weight of MVC or MVC monomer,
If TPU is less than 3 parts by weight, the paint using the resulting polymer will not have satisfactory flexibility, while if it exceeds 100 parts by weight, the paint using the resulting polymer will not have a satisfactory coating film. Hardness cannot be obtained. In the present invention, the TPU content in the produced polymer is preferably 5 to 60% by weight, more preferably 10 to 50% by weight.
Weight%. This is because if the amount is less than 5% by weight, it is difficult to obtain satisfactory flexibility in the resulting paint. On the other hand, if it exceeds 60% by weight, the resulting paint will not exhibit satisfactory coating hardness, which is not preferred. [Monomer copolymerizable with MVC] In the present invention, monomers copolymerizable with MVC include olefins such as ethylene and propylene, vinyl esters such as vinyl acetate, and n-
Vinyl ethers such as butyl vinyl ether,
Examples include acrylic esters such as butyl acrylate and 2-ethylhexyl acrylate, and methacrylic esters such as 2-ethylhexyl methacrylate. The amount used is preferably 50% by weight or less, more preferably 30% by weight or less in the MVC monomer. This is because if the content exceeds 50% by weight, the adhesion of the resulting paint will deteriorate. [Polymerization method] For the production of the thermoplastic resin used in the present invention, methods such as solution polymerization using an organic solvent as a solvent, suspension polymerization using water as a medium, and emulsion polymerization are adopted. The solvent used in solution polymerization may be any known solvent. For example, aromatic hydrocarbons such as toluene and xylene, alicyclic hydrocarbons such as cyclohexanone, ketone compounds such as methyl ethyl ketone and methyl isobutyl ketone, ester compounds such as butyl acetate and ethyl acetate, and ethers such as tetrahydrofuran are used. They may be used alone or in combination. The suspending agent used in suspension polymerization may be any known suspending agent. For example, partially saponified polyvinyl alcohol, methylcellulose, ethylcellulose, hydroxymethylcellulose, polyacrylic acid, vinyl ether-maleic anhydride copolymer, gelatin, calcium phosphate, etc. are used.
These may be used alone or in combination. In addition, the amount of these used is 0.01 to 0.01 to aqueous medium.
It is about 2% by weight. Known emulsifiers are used in emulsion polymerization. For example, nonionic surfactants such as polyoxyethylene alkyl ether, polyoxyethylene alkyl phenol ether, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene acyl ester, fatty acid salts, higher alcohol sulfate ester salts, alkylbenzene sulfonates, alkyl Anionic surfactants such as naphthalene sulfonates and alkyl phosphate salts, and cationic surfactants such as alkylamines, quaternary ammonium salts, and polyoxyethylene alkylamines are used. The charging ratio of organic medium or aqueous medium/(TPU+MVC or MVC monomer) in the production of thermoplastic resin is preferably 1/1 to 3/1. This means that the ratio is 1/
When the ratio is less than 1, polymerization becomes unstable, and when the ratio is 3/1
It is because it is not economically advantageous to exceed . The oil-soluble polymerization initiator used in the production of the thermoplastic resin may be any known polymerization initiator. For example, azo compounds such as azobisisobutylvaleronitrile, lauryl peroxide, di-
2-ethylhexyl peroxycarbonate, t-
There are organic peroxides such as butyl peroxypivalate. The amount used is about 0.01 to 2% by weight based on the MVC or MVC monomer at the time of preparation. The polymerization temperature is 30° to 70°C, preferably 40° to 60°C. This is not industrially advantageous since the polymerization rate tends to slow down below 30°C. Furthermore, if the temperature exceeds 70°C, the resulting polymer tends to have poor heat resistance, which is not preferable. In the present invention, known chain transfer agents such as trichlorethylene and mercaptoethanol may be used. [Paint for forming a leather tone coating film] The coating material for forming a leather tone coating film of the present invention is obtained by dissolving the above-mentioned thermoplastic resin in an organic solvent,
In addition, pigments, antifoaming agents, leveling agents,
Compounding agents such as a color separation prevention agent and a coating conditioner are added. The solvent used is not particularly limited, and includes, for example, aromatic hydrocarbons such as toluene and xylene, alicyclic hydrocarbons such as cyclohexanone, ketone compounds such as methyl ethyl ketone and methyl isobutyl ketone,
Ester compounds such as butyl acetate and ethyl acetate, and ethers such as tetrahydrofuran are used, and these may be used alone or in combination. In addition to the above-mentioned thermoplastic resin and solvent, the paint of the present invention usually contains titanium dioxide, Bengara, ocher,
Coloring pigments such as carbon black and phthalocyanine blue, extender pigments such as precipitated barium sulfate, talc, calcium carbonate, and clay, antifoaming agents such as silicone TSA-720, silicone YF-25, and silicone TSC920 manufactured by Toshiba Silicon Corporation. , leveling agent,
Paint conditioners such as color separation preventive agents are appropriately blended. Furthermore, if necessary, polyisocyanate is used as a crosslinking agent. The thermoplastic resin as the resin content in the paint of the present invention is 10 to 40% by weight as a resin solid content in the paint.
is preferable, and the content of pigments such as color pigments and extender pigments is preferably 1 to 35% by weight. The amounts of other paint adjusting aids and viscosity adjusting solvents are determined as appropriate depending on the resin and pigment. [Painting method] For painting, the above paint is diluted appropriately with a normal diluting solvent, and air spray painting, airless spray painting,
This is done by roll coater painting, flow coater painting, etc. [Example] Next, the present invention will be explained in more detail with reference to Examples and Comparative Examples. The coating conditions in each example are as follows. Air spray was used to dry the surface of an automobile armrest molded body, which had a leather tone formed by an uneven pattern on the surface, which was injection foam molded with soft vinyl chloride containing 70 parts of a plasticizer and a foaming agent. Painted to a film thickness of 20μm and heated to a temperature of 80℃.
Dry for 15 minutes at °C. Example 1 Polymerization was carried out using the polymerization recipe shown below. That is, raw materials other than vinyl chloride were charged into a stainless steel autoclave with an internal volume of 10, the air inside was replaced with _N2 , and then vinyl chloride was charged. A thermoplastic resin solution was obtained by reacting at 38°C for 20 hours. The reaction rate was 50%. (Composition at time of preparation) Part by weight TPU (Pandex T-5265) 100 Vinyl chloride 400 Methyl ethyl ketone 300 Toluene 300 2,2'-azobis(4-methoxy, 2,4-dimethylvaleronitrile) 0.5 (Copolymer composition) TPU 33wt % Vinyl chloride 67wt% Next, the following paint was prepared using the obtained thermoplastic resin solution. (Paint composition) Weight % Thermoplastic resin 25 Carbon black 10 MEK 35 Toluene 30 This paint was further diluted with toluene, applied to the surface to be painted with air spray, dried, and the following tests were conducted. Appearance The texture of the paint film was observed and the leather tone properties were examined. Adhesion: 100 at 2mm intervals using a goban tester
Draw the individual goban marks and peel off with cellophane tape. I counted the number of gobans left. Flexibility: The painted test piece was bent to check for wrinkles in the coating. The results obtained are shown in Table-1. Comparative Example 1 A similar test was conducted except that a commercially available two-component curing polyurethane paint (Toa Paint Co., Ltd., Tourethane #3000) was used instead of the paint of the present invention in Example 1. The results are shown in Table-1.

[Table] (c) Effects of the invention The paint for forming a leather tone coating film of the present invention has excellent leather tone properties, flexibility, and adhesion.
It is industrially useful as a paint for housing, automobile interior materials, office equipment, and cover materials for audio equipment.

Claims (1)

[Claims] 1. Based on 100 parts by weight of vinyl chloride monomer or a monomer mixture of vinyl chloride monomer and a monomer copolymerizable with vinyl chloride monomer, soluble in the monomer or monomer mixture An article having a leather tone, which is made of a thermoplastic resin obtained by polymerizing the monomer or monomer mixture in the presence of 3 to 100 parts by weight of a thermoplastic polyurethane elastomer having a softening point of 20 to 100 °C. Paint for surface finishing.