JPS627230B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an acrylic lacquer, and more particularly to an acrylic lacquer with abrasion resistance comprising the use as an essential component of a specific copolymer obtained with a specific amount of t-butyl methacrylate. and a lacquer for plastic coatings with excellent alcohol resistance. Lutker-type paints containing cellulose compounds have a wide range of uses because of their performance, such as drying properties and solvent resistance, as well as their ease of use. In particular, paints made of acrylic resins and cellulose compounds are widely used for coating plastic molded products. However, the reality is that conventional plastic coatings do not have sufficient wear resistance, such as scratches during packaging and exposure of the base material. However, as a result of intensive studies in view of the various drawbacks in the prior art as described above, the present inventors found that 5 to 95% by weight of t-butyl methacrylate (1) and (2) this t-butyl methacrylate ( The number average molecular weight obtained by polymerizing 5 to 95% by weight of a specific monomer as described below that can be copolymerized with 1).
5000 to 50000 and the glass transition point is 60
When a copolymer with a temperature of ~95°C and a copolymer containing a known and commonly used pigment, paint additive, and/or cellulose compound are applied to a plastic molded product, The present invention was completed based on the discovery that a coating film with excellent abrasion resistance and alcohol resistance can be provided. Here, the monomer (2) copolymerizable with t-butyl methacrylate (1) refers to methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate. , lauryl (meth)acrylate, stearyl (meth)acrylate, i-
It refers to 15 compounds such as butyl acrylate, tridecyl methacrylate, and styrene, and these can be used alone or in a mixture of two or more. The amount of the t-butyl methacrylate (1) used is 5 to 95% by weight, preferably 10 to 90% by weight in the resulting copolymer, while the amount of the above-mentioned copolymerizable monomer (2) The amount used is 5 to 95% by weight, preferably 10 to 90% by weight. If the amount of t-butyl methacrylate used is less than 5% by weight, the wear resistance and alcohol resistance will not be sufficient, whereas if it exceeds 95% by weight, there is a risk of cracks occurring, both of which are undesirable. . The copolymer obtained with such a monomer composition must first have a glass transition point within the range of 60 to 95°C, and the selection of monomers should also be made from this point of view. However, if the temperature is lower than 60℃, the wear resistance is not sufficient;
Anything higher than this is unfavorable because cracks are more likely to occur. The copolymer has a number average molecular weight of
It is also necessary that the number is in the range of 5,000 to 50,000, preferably in the range of 15,000 to 35,000. If the molecular weight is lower than 5,000, the abrasion resistance will not be sufficient, and if the molecular weight is higher than 50,000, it will be difficult to obtain sufficient spray workability, so both are not preferred. Although known and commonly used polymerization methods can be used to obtain the copolymer, a solution polymerization method is preferably used, using monomers such as those described above, and an aromatic hydrocarbon such as toluene or xylene as a solvent. Using esters such as ethyl acetate or butyl acetate, ketones such as methyl ethyl ketone or methyl isobutyl ketone, or alcohols such as n-butanol or i-butanol, azobisisobutyronitrile (AIBN),
The polymerization is preferably carried out in the presence of a known and commonly used radical generator such as benzoyl peroxide (BPO), t-butyl perbenzoate (TBPB) or t-butyl peroctoate (TBPO). The copolymer thus obtained can be diluted with an appropriate thinner and used as a clear paint, or it can be used as a lacquer in combination with pigments, paint additives, and/or cellulose compounds if necessary. You can also use Here, cellulose compounds such as nitrified cotton and cellulose acetate butyrate are used to increase the level of thinner resistance, drying properties, hardness and flexibility, and to increase the level of mechanical properties. Plasticizers or polyester resins are used, and in order to further improve anti-cissing properties, weather resistance and leveling properties, commonly known paint additives such as antifoaming agents, leveling agents, ultraviolet absorbers or antioxidants are used. It should be used in quantity. Further, as the coating method, known and commonly used methods such as brush coating, spray coating, or roll coating can be adopted. The lacquer of the present invention has particularly excellent abrasion resistance and alcohol resistance, but the reason for this effect is not clear, but it may be due to the t-butyl methacrylate used as a monomer. I think I'm deaf. Next, the present invention will be explained in detail with reference to Examples and Comparative Examples. In the following, "parts" mean "parts by weight" unless otherwise specified. Examples 1 to 3 and Comparative Examples 1 to 5 500 g of toluene was placed in a 4-necked flask equipped with a stirrer, an inert gas inlet, a thermometer, and a condenser.
Add 500g of n-butanol and raise the temperature.
When the temperature reached 100°C, the mixture shown in Table 1 was added dropwise over a period of 4 hours, and the same temperature was then maintained for 10 hours to carry out polymerization to produce the desired copolymer. Obtained. The number average molecular weight and glass transition point of the various copolymers obtained here are summarized in the same table. Next, for 100 parts of each of these copolymers,
Add 10 parts of aluminum paste (non-volatile content 65% by weight) to each and disperse them, then dilute with a thinner consisting of ethyl acetate/n-butanol/butyl cellosolve = 40/40/20 (weight ratio) to prepare a lacquer. did. Afterwards, air spray this to a film thickness of 15 mm.
Painted on a polystyrene plate so that it was μ, and heated at 60℃.
Baking was carried out for 30 minutes. Thereafter, the performance of each coating film obtained by leaving it at room temperature for 3 days was evaluated, and the results are summarized in the same table. 【table】

Claims (1)

[Claims] 1 (1) 5-95% by weight of t-butyl methacrylate
and (2) methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, i-butyl acrylate, At least one of the above t selected from the group consisting of tridecyl methacrylate and styrene.
- A number average molecular weight of 5000 to 5000, obtained by polymerizing butyl methacrylate (1) and 5 to 95% by weight of a copolymerizable monomer so that the total amount is 100% by weight.
50,000 and a glass transition point of 60 to 95°C as an essential component, and further contains pigments, paint additives, and/or cellulose compounds as necessary. car.