JPH0126629B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a new and useful primer composition for polypropylene resins, and the object of the present invention is to improve the paintability of the polypropylene resins without treatment. Provided is a resin composition that has a function as a primer for polypropylene resin materials and has good adhesion and solvent resistance when used as a material without undergoing any of the various surface treatments that require imparting it. There is something to do. [Prior art and problems to be solved by the invention] Paints made from alkyd resins, acrylic resins, epoxy resins, etc., which have been used in the past, cannot be applied to various molded products made from crystalline polyolefins with low polarity. It has almost no adhesion ability. For this reason, it has been proposed to use a maleic anhydride modified product of attack polypropylene or a maleic anhydride modified product of ethylene-propylene copolymer as a primer when painting such polypropylene materials. However, although they have good adhesion to the materials listed above, they have poor interlayer adhesion with the top coat layer and have shortcomings in solvent resistance. On the other hand, a method is known in which chlorinated polyolefin itself is used as a primer and acrylic resin is applied as a top coat layer, but even with this method, it is difficult to improve interlayer adhesion with the top coat layer, solvent resistance, and long-term durability. It has the disadvantage of poor long-term adhesion. [Means for Solving the Problems] However, as a result of intensive studies in view of the various drawbacks of the prior art as described above, the present inventors found that chlorinated polypropylene containing acid groups (carboxyl groups) and hydroxyl groups A composition comprising chlorinated polypropylene containing (hydroxyl groups), a solid resin capable of imparting tackiness, and a solvent, and furthermore a composition comprising a specific ethylene vinyl acetate copolymer, Excellent properties such as excellent adhesion even to untreated polypropylene resin, adhesion with top coat (interlayer adhesion), and adhesion during cold and heat cycles. The present invention was completed based on the discovery that the primer has the following properties. That is, the present invention uses (A) chlorinated polypropylene (a) having a chlorine content of 10 to 50% by weight and an acid value of 2 to 70 per solid content as essential components.
-1) and/or chlorinated polypropylene (a-2) having a hydroxyl value of 2 to 150 per solid content.
50 to 90 parts by weight, (B) is solid at room temperature, and
The chlorinated polypropylenes (a-1) and (a-2) are soluble in a solvent selected from the group consisting of aromatic, aliphatic, alicyclic, ketone, ester, alcohol and chlorinated polypropylenes. 50 to 10 parts by weight of a resin capable of imparting tackiness to ) and an appropriate amount of (C) a solvent, and the component (A) is ethylene vinyl acetate having a vinyl acetate content of 5 to 50% by weight. 0 to 70% by weight of the copolymer (a-3) and the chlorinated polypropylene (a-1) and/or (a-2).
The present invention provides a primer composition for polypropylene resin, which may be composed of 100 to 30% by weight. Here, the above-mentioned polypropylene resin refers to a propylene homopolymer or copolymer containing propylene as an essential constituent unit, and the most representative examples thereof include polypropylene homopolymer. , ethylene propylene copolymer or ethylene propylene diene terpolymer. In addition, the above-mentioned chlorinated polypropylene (a-
1) means that the chlorination rate is 10 to 50% by weight, preferably
This refers to chlorinated polypropylene containing 10 to 40% by weight and having an acid value of 2 to 70, preferably 5 to 50 per resin solid content; It refers to chlorinated polypropylene having a conversion ratio of 10 to 50% by weight, 10 to 40% by weight, and a hydroxyl value per resin solid content of 2 to 150, preferably 5 to 110. At that time, the chlorinated polypropylene (a-
1) or (a-2), the chlorination rate is
If it exceeds 50% by weight, the adhesion to various polypropylene resin materials as mentioned above will decrease, and conversely, if the chlorination rate is less than 10% by weight, it will lack storage stability. If the acid value of the chlorinated polypropylene (a-1) exceeds 70, the adhesion to various polypropylene resin materials will decrease, and conversely, the acid value of the chlorinated polypropylene (a-1) will decrease. is less than 2, this is not preferable because the interlayer adhesion with the top coat layer becomes poor. On the other hand, when the hydroxyl value of the chlorinated polypropylene (a-2) exceeds 150, the chlorinated polypropylene (a-2) a-2) Problems will arise in the stability of the solution itself and in adhesion to various polypropylene resin materials.On the other hand, if the hydroxyl value is less than 2, interlayer adhesion with the top coat layer will deteriorate. This is not desirable because it makes it inferior. By the way, as the component (A), which is the first essential component constituting the composition of the present invention, chlorinated polypropylene (a-1) and/or (a-2) listed above is sufficient. However, if further flexibility is required, the chlorinated polypropylene (a-1) and/or (a-2) may be used as the component (A). may be used in a mixed form with a specific ethylene vinyl acetate copolymer (a-3) as described below within a range of up to 70% by weight. These ethylene vinyl acetate copolymers (a-
3) In particular, the content of vinyl acetate is 5 to 5.
A range of 50% by weight, preferably 10-45% by weight is suitable. If the vinyl acetate content is less than 5% by weight, the interlayer adhesion with the top coat layer will be reduced, while if it exceeds 50% by weight, the resulting composition will have poor durability. It has disadvantages in solvent properties. And the chlorinated polypropylene (a-1)
The mixing ratio of the ethylene vinyl acetate copolymer (a-3) to (a-2) is 0 to 70% by weight of the ethylene vinyl acetate copolymer (a-3) to the chlorinated polypropylene (a-1). and (a-
100 to 30% by weight of 2), preferably 0 to 50% by weight
A proportion of 100 to 50% by weight is suitable. Such ethylene vinyl acetate copolymer (a-3)
If the amount used exceeds 70% by weight, it is undesirable because the adhesion to the various polypropylene resin materials mentioned above will be reduced. 100~ of chlorinated polypropylene (a-1) and/or (a-2) as described above
30% by weight and ethylene vinyl acetate copolymer (a-
Component (A) consisting of 0 to 70% by weight of 3) has excellent adhesion to the various polypropylene resin materials listed above, but even among these polypropylene resins, In the case of molded articles obtained using certain types of copolymers, it has been observed that the adhesion after the hot water resistance test is reduced. As a measure to improve the decrease in adhesion after the hot water resistance test or to further improve the solvent resistance as a primer,
and chlorinated polypropylene (a-
A solid resin that can impart tackiness to 1) and/or (a-2) and has the ability to adhere to various polypropylene resin materials, that is, a solid resin that is solid at room temperature and is aromatic or aliphatic. , soluble in a solvent selected from the group consisting of alicyclic type, ketone type, ester type, alcohol type and chlorine type,
The chlorinated polypropylene (a-1) and (a
-2) The solid resin (B) capable of imparting tackiness to the above-mentioned
It is preferable to mix it in a ratio of 10 to 50 parts by weight, preferably 10 to 40 parts by weight, to 90 to 50 parts by weight of component (A). A coating film having good adhesion and excellent solvent resistance can be obtained. Here, representative examples of the solid resin (B) include 100% carbonic acid resin (phenolic resin), natural resin-modified carbonic acid resin such as rosin-modified phenolic resin, natural resin-modified maleic acid resin such as rosin-modified maleic resin, and various Xylene resin, ketone resin, terpene polymer resin (terpene resin), α-pinene polymer, terpene/phenol polymer, various rosin resins, coumaron/indene polymer (coumaron/indene resin), alicyclic saturated hydrocarbon resin ,
Examples include aliphatic hydrocarbon resins, aromatic hydrocarbon resins, hydrogenated alicyclic hydrocarbon resins, and _C5 fraction petroleum resins, and these may be used alone or as a mixture of two or more. The amount of solid resin (B) used is 50
If it exceeds 1 part by weight, the resulting coating film will have insufficient flexibility, so the amount should be 50 parts by weight or less, more preferably 10 to 40 parts by weight. The solvent (C) is, of course, a solvent capable of dissolving the various tackifying resins (B) as listed above, that is, aromatic, aliphatic, alicyclic, ketone, and ester. Various types of solvents, including alcohol-based, alcohol-based, and chlorinated-based solvents, are all included. The primer composition of the present invention thus obtained has excellent long-term adhesion and adhesion in a broad sense, such as interlayer adhesion between the top coat layer and the top coat layer, and also has excellent solvent resistance. It provides a coating film with excellent coating performance, and among these, for chlorinated polypropylene-based primer compositions containing hydroxyl groups, "Burnok DN-950" is used.
By curing with various isocyanate prepolymers such as [non-yellowing isocyanate prepolymer manufactured by Dainippon Ink and Chemicals Co., Ltd.], interlayer adhesion with the top coat layer will not be adversely affected. This is particularly desirable since it can also improve the solvent resistance of the primer composition of the present invention. [Example] Next, the present invention will be specifically explained with reference to Examples and Comparative Examples. In the following, all parts and percentages are based on weight unless otherwise specified. Example 1 "Hardlene 14ML" [chlorinated polypropylene/maleic anhydride copolymer manufactured by Toyo Kasei Kogyo Co., Ltd.; solid content =
31%, chlorine content = 24.5%, acid value = 3.5] of 225.8
part, 20 parts of toluene and “Coumaron resin V-
120'' [Kumaron resin manufactured by Nippon Steel Chemical Co., Ltd.] was charged, the temperature inside the vessel was raised to 50℃, and the mixture was stirred until a homogeneous solution was obtained. When the solution became homogeneous, 124.2 parts of xylene was added. A resin solution with a solid content of 26.3% was obtained. Then, for this resin solution, resin solution:
"Taipeku CR-93": "MA-100" = 70:29.4:
Pigments were blended to give a weight ratio of 0.06 (solid content), and a paint was made by a conventional method. Here, the above-mentioned "Tiepeke CR-93" is a rutile type titanium oxide manufactured by Ishihara Sangyo Co., Ltd., and the above-mentioned "MA-100" is carbon black manufactured by Mitsubishi Chemical Industries, Ltd. Thereafter, the paint thus obtained was diluted with a thinner of xylene:ethyl acetate = 50:50 (weight ratio) using an Iwata cup for 12 seconds.
Next, this paint was sprayed onto a sheet made from "Noblen BC-3B" (a polypropylene homopolymer manufactured by Mitsubishi Yuka Co., Ltd.) and set.
After 10 minutes, a white paint prepared from ``Acrydik A-800'' [acrylic polyol manufactured by Dainippon Ink and Chemicals Co., Ltd.] and ``Bernok DN-950'' was applied.
Pigment concentration (PWC) using “Tiepeke CR-93”
xylene: ethyl acetate = 50:50
(Weight ratio) The thinner makes it 11 in Iwata Cup.
Apply the diluted solution to the coating sheet, let it settle for 10 minutes, and then heat it to 60℃ for 30 minutes.
Force dry for a minute. After 3 days of drying, a comprehensive evaluation of the physical properties of the paint film was made from both the sheet coated with the primer composition and the sheet coated with a top coat layer on top of the primer coat. I went. The results are summarized in Table 1. Example 2 Instead of "Hardren 14ML", 350 parts of "Superchron S-64" [chlorinated polypropylene/maleic anhydride copolymer manufactured by Sanyo Kokusaku Pulp Co., Ltd.; solid content = 20 ° C., chlorination rate =24.5%, acid value=
3.2] Example 1 except that it was changed to use
In the same manner as above, a resin solution with a solid content of 19.8% was obtained. Other than changing to use this resin solution,
Thereafter, it was made into a paint in the same manner as in Example 1, and the physical properties of the paint film were evaluated. Those results are the first
They are summarized in the table. Example 3 The same procedure was carried out except that the same amount of "Betsukasite 1111" [a natural resin-modified maleic acid resin manufactured by Dainippon Ink and Chemicals Co., Ltd.] was used instead of "Kumaron Resin V-120". A resin solution having a solid content of 25.3% was obtained in the same manner as in Example 1. Next, a paint was prepared in the same manner as in Example 1, except that this resin solution was used, and the physical properties of the paint film were evaluated. The results are summarized in Table 1. Example 4 Instead of "Hardren 14ML", 466.7 parts of "Hardren 14LLB・AH10" (chlorinated polypropylene/β-hydroxyethyl acrylate copolymer manufactured by the same company; solid content = 17.3%, chlorine content = 24)
A resin solution having a solid content of 19.5% was obtained in the same manner as in Example 1, except for changing to using %, hydroxyl value = 6.7). Next, a paint was prepared in the same manner as in Example 1, except that this resin solution was used, and the physical properties of the paint film were evaluated. The results are summarized in Table 1. Example 5 In a reactor equipped with a stirrer and a cooler, 193.5 parts of "Hardrene 14ML" and "Elvax 150" were added.
20 parts of ethylene vinyl acetate copolymer (manufactured by Mitsui Polychemical Co., Ltd.; vinyl acetate content = 33%), 20 parts of "Kumaron Resin V-120", 30 parts of toluene, and 236.5 parts of xylene were prepared. , the temperature inside the vessel
The mixture was heated to 50°C and stirred until a homogeneous solution was obtained. A resin solution with a solid content of 21.3% was obtained. Next, a paint was prepared in the same manner as in Example 1 except that this resin solution was used, and the physical properties of the paint film were evaluated. These results are summarized in the first
Shown in the table. Comparative Example 1 466.7 parts of "Hardren 14LLB" (chlorinated polypropylene made by the same company; solid content = 15%, chlorination rate = 27%) was used instead of "Hardren 14ML", and this Example 1, except that no xylene was used during the preparation.
A control resin solution having a solid content of 19.8% was obtained in the same manner as above. Next, a paint was prepared in the same manner as in Example 1 except that this resin solution was used, and the physical properties of the paint film were evaluated. The results are summarized in Table 1. Comparative Example 2 Abstaining from the use of "Kumaron Resin V-120" at all,
Therefore, "Hardren 14ML": "Taipeku"
CR-93":"MA-100"=70:29.4:0.06 (solid content weight ratio) Except for changing the composition ratio, a paint was prepared in the same manner as in Example 1, and the control thus obtained The physical properties of the coating film were evaluated using the primer composition for Those results are the first
They are summarized in the table.

〔Effect of the invention〕

As is clear from the results in Table 1, the primer composition of the present invention has excellent adhesion to an inert polypropylene resin material that has not been subjected to any surface treatment, and also has excellent adhesion to the top coat layer. It is known that it provides a useful coating film with excellent interlayer adhesion.

Claims (1)

[Claims] 1 (A) The ethylene vinyl acetate copolymer (a-3) having a vinyl acetate content of 5 to 50% by weight may be contained in a range of up to 70% by weight, and a chlorine content of 10 to 50% by weight.
50% by weight and acid value per solid content of 2 to 70
5 to 90 parts by weight of chlorinated polypropylene (a-1) and/or chlorinated polypropylene (a-2) having a hydroxyl value of 2 to 150 per solid content,
(B) The above-mentioned chlorine is solid at room temperature and soluble in a solvent selected from the group consisting of aromatic, aliphatic, alicyclic, ketone, ester, alcohol and chlorine solvents. polypropylene (a-1)
and 50% of the resin capable of imparting tackiness to (a-2).
A primer composition for polypropylene resin, comprising as essential components ~10 parts by weight and an appropriate amount of (C) a solvent.