JPS642150B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a coating composition for polyolefin resins that provides a coating film with excellent appearance and good adhesion by curing at room temperature or low temperature. In recent years, various types of plastics have come to be used as materials for automobile parts and household electrical appliances, and in particular, the use of plastics to reduce the weight of automobile parts has been avoided in order to save energy, and this trend seems to be expanding. It is. Currently, various types of plastics are used in large quantities, but polyolefin resins are only partially used despite being relatively inexpensive. This is largely due to the lack of good coating compositions for polyolefin resins, and in particular the property of polyolefins, which makes it difficult for coatings to adhere.Therefore, the development of coating compositions that have good adhesion to polyolefin resins is greatly needed. It is expected. In response to these demands, various coating compositions that adhere to polyolefins are currently being developed. As one of these, studies are underway to utilize the fact that chlorinated polyolefin adheres well to polyolefin as an adhesive aid for polyolefin. However, apart from the method of using chlorinated polyolefin as an undercoat and then topcoating with another resin, the compatibility between the chlorinated polyolefin and the paint resin is limited for one-coat finishes that contain chlorinated polyolefin in the paint. There are problems in terms of poor coating film appearance, and if it is desired to improve the coating film appearance, there is a limit to the amount of chlorinated polyolefin that can be used, and there are problems with adhesion. Therefore, the inventors of the present invention have conducted repeated research with the aim of solving the above problems, and have found that a one-coat finish has good adhesion, an excellent appearance, and excellent performance such as gasoline resistance and solvent resistance. We have discovered a composition that forms a coating film. That is, in the present invention, the weight ratio of the acrylic monomer to the chlorinated polyolefin is in the range of 98/2 to 30/70, and the acrylic monomer contains 100% by weight of (1) basic nitrogen-containing acrylic; System monomer 0.2-30% by weight (2) Acrylic acid or methacrylic acid and aliphatic 1
Obtained by polymerizing an acrylic monomer consisting of 35 to 99.8% by weight of an ester with a alcohol or a mixture thereof (3) and 0 to 60% by weight of other copolymerizable monomers in the presence of a chlorinated polyolefin. A coating composition consisting of a copolymer composition () and a compound or resin () having two or more epoxy groups per molecule. Component (1) of the acrylic copolymer composition (), that is, the basic-containing acrylic monomer (), is for reacting with and crosslinking, dimethylaminoethyl acrylate or methacrylate, diethylaminoethyl acrylate or methacrylate, t. -Butylaminoethyl acrylate or methacrylate is preferably used. The amount used is 0.2-30% by weight, but preferably
It is 0.5-20% by weight. Component (2) of the acrylic copolymer composition (2) is preferably an ester of acrylic acid or methacrylic acid and a monovalent acyclic or cyclic aliphatic monohydric alcohol, particularly methanol, ethanol, propanol, butanol, etc. and mixtures thereof, preferably 35 to 99.8% by weight of the monomer, preferably 50 to 80% by weight of the monomer.
is used. As component (3) of the acrylic copolymer composition (), styrene and a small amount of acrylic acid and/or methacrylic acid are preferably used, but in addition, α-methylstyrene, vinyltoluene, acrylonitrile, vinyl acetate, 2-hydroxy ethyl acrylate or methacrylate,
Anything that can be copolymerized with components (1) and (2), such as 2-hydroxypropyl acrylate or methacrylate, acrylamide, methacrylamide, glycidyl acrylate or methacrylate, can be used. This usage amount is 0 for styrene etc.
~60% by weight, preferably 10-40% by weight can be used.
The content of acrylic acid, methacrylic acid, etc. is preferably 10% or less, and the content of other monomers is preferably 20% or less. As the chlorinated polyolefin, chlorinated polypropylene, chlorinated polyethylene, etc. are preferably used. The weight ratio of the acrylic monomer to the chlorinated polyolefin is from 98/2 to 30/70, preferably from 90/10 to 50/50. The above acrylic copolymer composition () is polymerized by solution polymerization in the presence of chlorinated polyolefin.
That is, a polymerization initiator such as an azobis-based and/or peroxide-based initiator is used in the presence of an aromatic solvent such as toluene, an alcoholic solvent such as isobutanol, and/or an ester solvent such as ethyl acetate, Polymerization is carried out by conventional methods.
Although it depends on the amount of chlorinated polyolefin used, aromatic solvents are mainly preferred. As the compound or resin having two or more epoxy groups per molecule, glycidyl ether of polyhydric alcohol is preferably used. That is, ethylene glycol diglycidyl ether, glycerol polyglycidyl ether, sorbitol polyglycidyl ether, and the like are preferably used, but the present invention is not limited thereto. For example, any material containing a substance having two or more epoxy groups per molecule can be used, such as an acrylic resin copolymerized with glycidyl acrylate or methacrylate. The blending ratio of the acrylic copolymer composition () and the epoxy compound or resin () is
Basic nitrogen atom (gram atom) in parentheses/oxygen atom (gram atom) of epoxy group in parentheses is preferably about 0.3 to 3.0, but is not limited thereto. In the composition of the present invention, it is desirable to mix the acrylic copolymer composition (2) and the epoxy compound or resin (2) immediately before applying it to the object to be coated. If necessary, add a composition containing an epoxy compound or resin () to a composition containing an acrylic copolymer composition () to which pigments, additives, solvents, etc. are added, if necessary, and stir. It is preferable to apply the coating to the object without leaving it for a long time, adding a solvent and other additives if necessary. Furthermore, if necessary, other resins may be added to the chlorinated polyolefin. The applied coating film is dried at room temperature or, if necessary, by heating at a relatively low temperature, and a cured coating film is formed by a crosslinking reaction. It cures at a relatively low temperature and provides sufficient performance, but there is no problem even if it is cured at a high temperature. The feature of the present invention is that a specific acrylic monomer is polymerized in the presence of a chlorinated polyolefin in a coating film forming method that uses a compound or resin having an epoxy group as a crosslinking agent in the crosslinking reaction of an acrylic resin. The point is that the resulting acrylic copolymer composition is used. It is thought that by this method, the acrylic copolymer and chlorinated polyolefin, which had conventionally had relatively poor compatibility, are bonded to the acrylic monomer or copolymer to a part of the chlorinated polyolefin, and therefore chlorinated. It is characterized in that the affinity of the composition consisting of polyolefin and acrylic polymer is greatly improved, and the following effects appear. If the composition of the present invention is used, the composition will have excellent adhesion to polyolefin resins and a good surface condition.
A coating film with excellent appearance can be obtained with a one-coat finish. Furthermore, these coating films have much better performance, such as gasoline resistance, solvent resistance, and alkali resistance, than those obtained by air-drying or similar methods other than those of the present invention. In other words, if the composition of the present invention is used, it will save resources, have less toxicity due to the system using isocyanates, have particularly good adhesion to substrates, and improve appearance, physical performance, gasoline resistance, and chemical resistance. A high-performance coating film with excellent properties such as durability and water resistance can be obtained. The composition of the present invention is preferably used for coating polyolefin resins, preferably polypropylene resins, and can also be used for coating other building materials such as plastics, wood, and concrete. In order to clarify the effects of the present invention, examples thereof are shown below. Example 1 In a flask equipped with a condenser, a thermometer, and a stirrer, 70 parts of toluene and Hardene-15LLB (chlorinated polypropylene manufactured by Toyo Kasei Co., Ltd., solid content 30
%), 12 parts of dimethylaminoethyl methacrylate, 35 parts of methyl methacrylate, 23 parts of butyl acrylate, 30 parts of styrene, and 1 part of azobisisobutyronitrile, stirred at 80°C for 2 hours, and then stirred at 80°C every 2 hours. 0.3 parts of azobisisobutyronitrile was added twice, and the polymerization was completed in a total of 20 hours to obtain an acrylic copolymer composition (2). The nonvolatile content of the composition was 39.9%. 100 parts of sorbitol polyglycidyl ether (Denacol EX-611 manufactured by Nagase Sangyo Co., Ltd.)
After adding 3 parts and stirring, diluting with toluene to an appropriate viscosity, it was applied to a commercially available polypropylene resin plate using an applicator. After being left at 23°C for 3 days, a coating test was conducted. The dried coating film was transparent, uniform, and glossy, and had very good adhesion. Comparative Example 1 In a flask similar to Example 1, 100 parts of toluene,
12 parts of dimethylaminoethyl methacrylate, 35 parts of methyl methacrylate, 23 parts of butyl acrylate
1 part, 30 parts of styrene, and 1 part of azobisisobutyronitrile, stirred at 80℃ for 2 hours, then 2
Azobisisobutyronitrile 0.3 times per hour 8 times
The polymerization was completed in a total of 20 hours, and an acrylic copolymer resin solution was obtained. The nonvolatile content was 49.9%. 40 of these are hard-lenned.
After adding 67 parts of 15LLB and 3 parts of Denacol EX-611 and stirring well, diluting with toluene to an appropriate viscosity, a coating film was prepared in the same manner as in Example 1 and tested. The dried coating was uneven, had poor smoothness, lacked gloss, and had uneven adhesion. Example 2 100 parts of toluene was added to the same flask as in Example 1.
Hardren-15LLE83 parts, dimethylaminoethyl methacrylate 10 parts, methyl methacrylate 60 parts
15 parts of ethyl acrylate, 15 parts of n-butyl methacrylate, and 1 part of azobisisobutyronitrile, and polymerization was carried out in the same manner as in Example 1 to obtain an acrylic copolymer composition () with a nonvolatile content of 44.0%. Ta. Of this, 55 parts were added to diglycerol polyglycidyl ether (Denacol, manufactured by Nagase Sangyo Co., Ltd.).
After adding 2.5 parts of EX-421) and stirring and diluting with toluene to an appropriate viscosity, a coating film was prepared in the same manner as in Example 1 and tested. The dried coating film was uniform, had excellent smoothness, and had good adhesion. Comparative Example 2 In a flask similar to Example 1, 100 parts of toluene,
10 parts of dimethylaminoethyl methacrylate, 60 parts of methyl methacrylate, 15 parts of ethyl acrylate
Polymerization was carried out in the same manner as in Example 1 except that 15 parts of n-butyl methacrylate and 1 part of azobisisobutyronitrile were added, and chlorinated polypropylene was not included. Obtained. 40 of these include Denacol EX
-Add 2.5 parts of 421, and add Hardren-15LLB
After adding 40 parts and stirring well, a coating film was prepared in the same manner as in Example 1 and tested. The dried coating film was uneven and had poor smoothness, and its adhesion was uneven. Example 3 2.5 parts of Denacol EX-421 was added to 55 parts of the acrylic copolymer composition () obtained in Example 2, and further 25 parts of Hardren 15-LLB were added and stirred well, followed by the same method as in Example 1. A coating film was prepared and tested. The dried coating film had excellent smoothness and very good adhesion. Comparative Example 3 To 6 parts of the acrylic copolymer resin solution obtained in Comparative Example 2, 10 parts of toluene, 30 parts of titanium oxide, and sand grinder beads were added and shaken to disperse the pigment. Add 100 parts of acrylic copolymer resin solution to this,
6 parts of Denacol EX-611 was blended, Example 4 below.
A test plate was prepared and tested in the same manner as above. As a result, satisfactory adhesion could not be obtained. The results are shown in Table-1. Example 4 To 12 parts of the acrylic copolymer composition obtained in Example 2, 10 parts of toluene, 30 parts of titanium oxide (Typer 7R-930 manufactured by Ishihara Sangyo Co., Ltd.) and sand grinder beads were added and shaken. and dispersed the pigment. This was mixed with 138 parts of acrylic copolymer composition () and 6 parts of Denacol EX-611, diluted with aromatic thinner to an appropriate viscosity, and spray-painted onto a commercially available polypropylene resin board.
After standing for 1 hour, dry at 70℃ for 30 minutes, then dry at 23℃
After drying for 3 days, the coating was tested. The surface condition, adhesion, and other properties were good. The results are shown in Table-1. Comparative Example 4 To 6 parts of the acrylic copolymer resin solution obtained in Comparative Example 2, 10 parts of toluene, 30 parts of titanium oxide, and sand grinder beads were added and shaken to disperse the pigment. Add 100 parts of acrylic copolymer resin solution to this,
Denacol EX - 6 parts of 611, Hardren 15 -
43g of LLB was blended and the same test as in Example 4 was conducted. As a result, the gloss was low and the appearance of the coating film was poor. The results are shown in Table-1. 【table】

Claims (1)

[Claims] 1. The weight ratio of the acrylic monomer to the chlorinated polyolefin is in the range of 98/2 to 30/70, and the content of 100% by weight of the acrylic monomer is (1) containing basic nitrogen; Acrylic monomer 0.2-30% by weight (2) Acrylic acid or methacrylic acid and aliphatic 1
Obtained by polymerizing an acrylic monomer consisting of 35 to 99.8% by weight of an ester with a alcohol or a mixture thereof (3) and 0 to 60% by weight of other copolymerizable monomers in the presence of a chlorinated polyolefin. A coating composition comprising a copolymer composition () and a compound or resin () having two or more epoxy groups per molecule.