JPH05222320A - Primer composition - Google Patents

Abstract

PURPOSE:To prepare a primer compsn. which adheres well to the surface of a polyolefin molding and bonds a coating film strongly enough to the surface by grafting an unsatd. carboxylic acid (anhydride) onto an olefin polymer and chlorinating the resulting graft copolymer. CONSTITUTION:A graft copolymer is prepd. by grafting 0.01-10wt. % (based on the copolymer) unsatd. carboxylic acid (anhydride) onto an olefin polymer comprising 15-90mol% propylene units and 85-10mol% 4-6C alpha-olefin units and having an intrinsic viscosity eta of 0.8-2.0dl/g. The graft copolymer is chlorinated and dissolved in an org. solvent to give a primer compsn. which comprises 5-50 pts.wt. chlorinated copolymer contg. 5-35wt.% chlorine and 95-50 pts.wt. org. solvent. The compsn. adheres well to the surface of a polyolefin molding and bonds a coating film strongly enough to the surface without vapor cleaning with 1,1,1-trichloroethane.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a primer composition, and more particularly to a primer composition which can be undercoated on a molded article to improve the adhesion of the paint to the surface of the molded article.

[0002]

2. Description of the Related Art Conventionally, a surface of a molded product of polyolefin such as polypropylene is coated to increase its added value. However, in general, polyolefin has a poor polarity and the adhesion of paint is poor. Therefore, conventionally, the surface of the molded product is treated with a primer in advance to improve the adhesion and adhesion of the paint.
The present inventors have found that when a propylene / ethylene copolymer grafted with maleic anhydride is used as a primer, it exhibits good adhesion to materials and paints, and has previously proposed. (Japanese Patent Publication No. 59-42693, No. 62-
No. 21027), it was also discovered and previously proposed that a modified product obtained by graft-copolymerizing a monomer having a hydroxy group with a hydrogenated product of a styrene-conjugated diene-styrene ternary block copolymer was proposed. .. (Japanese Patent Laid-Open No. 2-110168)

[0003]

However, conventional primer compositions including the above-mentioned primer compositions must be applied after steam-cleaning the surface of a molded article with 1,1,1-trichloroethane. Since a coating film having good adhesion could not be obtained, there was a problem that the working environment was deteriorated by 1,1,1-trichloroethane and eventually the ozone layer was destroyed.

Therefore, an object of the present invention is to apply to a resin molded product, particularly a molded product of polyolefin such as polypropylene, without adhering to steam cleaning with 1,1,1-trichloroethane, to improve the adhesion to the surface. An object of the present invention is to provide a primer composition capable of obtaining a coating film having excellent peel strength.

[0005]

In order to solve the above-mentioned problems, the present invention provides, as a first embodiment, a propylene unit (a) content of 15 to 90 mol% and an α of 4 to 6 carbon atoms.
-Olefin unit (b) content 10-85 mol%
(The total content of (a) and (b) is 100 mol%), and the olefin polymer having an intrinsic viscosity [η] of 0.8 to 2.0 dl / g is mixed with an unsaturated carboxylic acid and Chlorination modification having a chlorine content of 5 to 35% by weight, which is obtained by graft-copolymerizing 0.1 to 10% by weight of at least one graft copolymerization unit selected from anhydrides, and further chlorinating. It is intended to provide a primer composition containing 5 to 50% by weight of a copolymer and 95 to 50% by weight of an organic solvent.

The present invention also provides, as a second embodiment,
The content of the propylene unit (a) is 15 to 90 mol% and the content of the α-olefin unit (b) having 4 to 6 carbon atoms is 10.
To 85 mol% (the total content of (a) and (b) is 100 mol%), and the intrinsic viscosity [η] is 0.8 to 2.0 d.
A chlorinated polymer having a chlorine content of 5 to 35% by weight, which is obtained by chlorinating an olefin polymer having an amount of 1 / g, and at least 1 selected from unsaturated carboxylic acids and anhydrides thereof.
Chlorinated modified copolymer 5 to 50 formed by graft copolymerization so as to contain 0.1 to 10% by weight of a graft copolymerized unit
The present invention provides a primer composition containing 100% by weight and 95 to 50% by weight of an organic solvent.

The α-olefin is 1-butene, 1-
Pentene, 4-methyl-1-pentene, 3-methyl-1
-It is preferably at least one selected from pentene and 1-hexene.

Hereinafter, the primer composition of the present invention (hereinafter,
"The composition of the present invention" will be described in detail.

The composition of the present invention comprises a chlorinated modified copolymer containing at least one selected from unsaturated carboxylic acids and their anhydrides as graft copolymerized units in an olefin polymer and further containing chlorine. , And an organic solvent as a main component.

The olefin polymer used in the present invention is a copolymer of propylene and an α-olefin having 4 to 6 carbon atoms, and has a propylene unit (a) derived from propylene and 4 to 6 carbon atoms. α derived from α-olefin
-Olefin units (b). Examples of the α-olefin having 4 to 6 carbon atoms include 1-butene, 1-pentene, 4-methyl-1-pentene, 3-methyl-1-pentene and 1-hexene.
These may be used alone or in combination of two or more. Among these, 1-butene is particularly preferable.

The content of the propylene unit (a) in this olefin polymer is 15 to 90 mol%, preferably 30 to 80 mol%. Also, the carbon number is 4 to 6.
The content of the α-olefin unit (b) is 10 to 85 mol%, preferably 20 to 70 mol%. The total content of the propylene unit (a) and the α-olefin unit (b) is 100 mol%.

The intrinsic viscosity [η] of this olefin polymer measured in decalin at 135 ° C. has an appropriate molecular weight, and the chlorinated modified copolymer has good solubility in an organic solvent and good solution viscosity. In terms of obtaining a polymer, 0.8-2.
It is in the range of 0 dl / g, preferably 0.9
˜1.5 dl / g.

The unsaturated carboxylic acid and its anhydride used as the graft copolymerized unit in the present invention include unsaturated monocarboxylic acids such as acrylic acid and methacrylic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid and allyl succinic acid. Unsaturated dicarboxylic acids such as acids, mesaconic acid, glutaconic acid, nadic acid, methyl nadic acid, tetrahydrophthalic acid, methylhexahydrophthalic acid, maleic anhydride, itaconic anhydride, citraconic anhydride, allylsuccinic anhydride, glutaconic anhydride Anhydrous unsaturated dicarboxylic acid such as nadic acid anhydride, methyl nadic acid anhydride, tetrahydrophthalic acid anhydride, and methyl hexahydrophthalic acid anhydride can be used. These graft copolymerized units are 1
A single kind or a combination of two or more kinds may be contained in the chlorinated modified copolymer. Among these graft copolymerized units, maleic acid, maleic anhydride, nadic acid and nadic anhydride are preferable.

The chlorinated modified copolymer used in the present invention contains these graft copolymerized units in an amount of 0.1 to 10% by weight, preferably 0, from the viewpoint of adhesion to a coating material and water resistance of a coating film. 2 to 7% by weight, more preferably 0.3 to 5
% By weight.

The chlorine content of this chlorinated modified copolymer is high because it has good solubility in an organic solvent, no insoluble matter remains in the solution, and a good coating appearance can be obtained. It is 5 to 35% by weight, preferably 12 to 28% by weight, from the viewpoint of obtaining a coating film having cohesive force.

The chlorinated modified copolymer used in the present invention is produced by graft-copolymerizing a graft-copolymerization unit with the above-mentioned olefin polymer, and then further chlorinating.
Alternatively, it may be carried out by any method of graft-copolymerizing a graft-copolymerization unit to a chlorinated polymer obtained by chlorinating the olefin polymer. Normal,
The method performed after the graft copolymerization of the olefin polymer is preferable.

The method for graft-copolymerizing at least one graft copolymerization unit selected from unsaturated carboxylic acids and their anhydrides onto the olefin-based polymer or chlorinated polymer is not particularly limited, and various known methods can be used. The method of is mentioned. For example, a method of dissolving the olefin polymer or chlorinated polymer in an organic solvent, adding the graft copolymerization unit and the radical polymerization initiator, and stirring with heating to perform graft copolymerization: the olefin polymer or A method in which a chlorinated polymer is melted by heating, and a graft copolymerization unit and a radical polymerization initiator are added to the resulting melt and stirred to carry out graft copolymerization: or graft copolymerization by supplying each component to an extruder Method: The olefin polymer or chlorinated polymer powder is impregnated with a solution in which the graft copolymerization unit and the radical polymerization initiator are dissolved in an organic solvent, and then the mixture is heated to a temperature at which the powder does not dissolve and grafted. Examples thereof include a method of copolymerization.

In this graft copolymerization, the ratio of the radical polymerization initiator / graft copolymerization unit used is usually 1/100 to 3/5, preferably 1/20 to 1 in molar ratio.
The range is / 2.

The radical polymerization initiator used in the graft copolymerization reaction may be any one as long as it promotes the reaction between the olefin polymer or chlorinated polymer and the graft copolymerization unit, and particularly an organic peroxide compound. , Organic perester compounds are preferred. Specific examples of the organic peroxide compound include benzoyl peroxide, dichlorobenzoyl peroxide, dicumyl peroxide,
Di-tert-butyl peroxide, 2,5-dimethyl-2,5-di (peroxybenzoate) hexyne-
3,1,4-bis (tert-butylperoxyisopropyl) benzene, lauroyl peroxide, tert
-Butyl peracetate, 2,5-dimethyl-2,5-
Di (tert-butylperoxy) hexyne-3,2
5-dimethyl-2,5-di (tert-butylperoxide) hexane and the like can be mentioned. Specific examples of the organic perester compound include tert-butylbenzoate and t.
tert-butyl perphenyl acetate, tert-butyl perisobutyrate, tert-butyl per-se
c-octoate, tert-butyl perpiperate,
Examples include cumyl perpiperate, tert-butyl perdiethyl acetate, and the like. In addition, other azo compounds,
Examples include 2,2'-azobisisobutyronitrile and dimethylazoisobutyronitrile. Among these, dicumyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di (t
Dialkyl peroxides such as ert-butylperoxy) hexyne-3,2,5-dimethyl-2,5-di (tert-butylperoxy) hexane and 1,4-bis (tert-butylperoxyisopropyl) benzene are preferred.

Chlorination of the modified copolymer by graft copolymerization or chlorination of the olefin-based polymer is carried out by dissolving the modified copolymer or the olefin-based polymer in a suitable solvent or dispersing it. It can be performed in the state where it was made to.

The solvent used for chlorination includes
For example, hexane, heptane, octane, decane, dodecane, an aliphatic hydrocarbon such as tetradodecane, methylcyclopentane, cyclohexane, methylcyclohexane,
Alicyclic hydrocarbons such as cyclooctane and cyclododecane,
Aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, cumene, ethyltoluene, trimethylben, diisopropylbenzene, chlorobenzene, bromobenzene, o-dichlorobenzene, carbon tetrachloride, carbon tetrabromide, chloroform, bromoform, trichloroethane, Halogenated hydrocarbons such as trichloroethylene, tetrachloroethane and tetrachloroethylene are preferred.

The chlorination reaction is preferably carried out in the above solvent by introducing chlorine gas until a predetermined chlorine content is reached.
In carrying out the chlorination reaction, ultraviolet rays or visible rays may be irradiated, or a radical generator may be used for the purpose of efficiently proceeding the reaction. The temperature of the chlorination reaction is usually 50 to 120 ° C., and the reaction time is about 0.
The range of 5 to 5 hours is common.

The chlorinated modified copolymer used in the present invention preferably has an intrinsic viscosity [η] of 0.2 to 1.5 dl / g, particularly 0.3 to 1.2 dl / g. ..

The organic solvent which is another essential component of the composition of the present invention includes, for example, aromatic hydrocarbons such as benzene, toluene and xylene, and aliphatic hydrocarbons such as hexane, heptane, octane and decane. Cyclohexane,
Alicyclic hydrocarbons such as cyclohexene and methylcyclohexane, aliphatic alcohols such as ethanol and isopropyl alcohol, ketone solvents such as acetone, methyl isobutyl ketone and methyl ethyl ketone, halogenation of trichloroethylene, dichloroethylene and chlorobenzene. Hydrocarbons may be mentioned. These are even one kind 2
You may use in the mixed system of 1 or more types. Among these, aromatic hydrocarbons are preferable, and alkyl group-substituted aromatic hydrocarbons are particularly preferable.

The mixing ratio of the chlorinated modified copolymer and the organic solvent in the primer composition of the present invention is such that the chlorinated modified copolymer is 5 to 50% by weight, and the organic solvent is 95 to 50% by weight, preferably chlorine. Chemically modified copolymer 10 to 45% by weight
The organic solvent is 90 to 60% by weight.

The primer composition of the present invention comprises, in addition to the chlorinated modified copolymer and the organic solvent, various stabilizers such as an antioxidant, a weather resistance stabilizer and a heat resistance inhibitor, titanium oxide and an organic solvent, if necessary. A component such as a coloring agent such as a pigment, a conductivity-imparting agent such as carbon black or ferrite may be contained.

The composition of the present invention is effective as a primer which is applied to the surface of a molded article made of polyolefin or other polymer to improve the adhesion of the paint to the surface. In particular, the composition of the present invention includes, for example, high-pressure process polyethylene, medium- and low-pressure process polyethylene, polypropylene, poly-4-methyl-pentene, polyolefins such as polystyrene, ethylene / propylene copolymers, ethylene / butene copolymers, and propylene. -It can be suitably used for a molded article made of a polyolefin copolymer such as butene copolymer.

Further, the composition of the present invention comprises, in addition to the above-mentioned polyolefins and other polymers, molded articles made of polypropylene and synthetic rubber, polyamide resins, unsaturated polyester resins, polybutylene terephthalate resins, polycarbonate resins and the like. It can also be used for molded products such as automobile bumpers, and also for surface treatment of steel plates and electrodeposited steel plates. In addition, polyurethane resin, fatty acid-modified polyester resin, oil-free polyester resin, melamine resin, epoxy resin, etc. as the main component, a primer, an adhesive, etc., is applied as an undercoat on the surface and the adhesion of the paint, etc. to that surface It can also be used to form a coating film having excellent image clarity and low temperature impact resistance.

The composition of the present invention is a coating film especially when the molded article to which the composition is applied is blended with an inorganic filler such as talc, zinc white, glass fiber, titanium white, magnesium sulfate and the like, a pigment and the like. It is possible to form a primer coating film having good adhesion. In addition to the above, the molded product may also contain various stabilizers, ultraviolet absorbers, hydrochloric acid absorbers and the like.

As the stabilizer preferably used, for example, 2,6-di-t-butyl-4-methylphenol,
Tetrakis [methylene (3,5-di-t-butyl-4-
Hydroxyphenyl) propionate] methane, metaoctadecyl-3- (4'-hydroxy-3,5-di-t
-Butylphenyl) propionate, 2,2'-methylenebis (4-methyl-6-t-butylphenol),
4,4'-butylidene bis (3-methyl-6-t-butylphenol), 4,4'-thiobis (3-methyl-6)
-T-butylphenol), 2,2-thiobis (4-methyl-6-t-butylphenol), 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-). Hydroxybenzyl) benzene, phenolic stabilizers such as 1,3,5-tris (2-methyl-4-hydroxy-5-t-butylphenol) butane, dilaurylthiodipropionate, distearylthiodipropionate, etc. Examples thereof include sulfur stabilizers and phosphorus stabilizers such as tridecyl phosphite and trinonylphenyl phosphite.

The ultraviolet absorbers preferably used include, for example, 2-hydroxy-4-octoxybenzophenone, 2-ethylhexyl-2-cyano-3,3-diphenyl acrylate, paraoctylphenyl salicylate and the like. it can. As the hydrochloric acid absorbent, for example, calcium stearate or the like is preferably used.

The composition of the present invention is suitable for spray application to a molded article, and is sprayed on the surface of the molded article with a spray gun, for example. The molded product may be applied at room temperature, and after application, it is dried by an appropriate method such as natural drying or forced drying by heating to form a coating film. In this way, after applying the composition of the present invention to the surface of the molded article and drying to form a coating film,
The paint can be applied onto the coating film of the molded product by a method such as electrostatic coating, spray coating, brush coating and the like.
These paints may be applied by undercoating and then overcoating. After applying the paint, the paint is Nichrome wire,
The coating film is cured by a usual method such as infrared ray or high frequency heating to obtain a molded product as a product. The method for curing the coating film is appropriately selected depending on the material and shape of the molded product, the properties of the coating material and the like.

[0033]

EXAMPLES Examples will be shown below, but the present invention is not limited to these examples. In addition, the graft amount in the following is oxygen analysis (manufactured by HERAEUS).
CHN-O-RAPID) to determine the oxygen content,
It is calculated.

In the following, the physical properties of the coating film were tested as follows. Cross-cut test A cross-cut test piece was prepared according to the method of the cross-cut test described in JIS K 5400, and cellophane tape (cellophane tape manufactured by Nichiban Co., Ltd.) was pasted on the cross-cut test. This was quickly pulled in the 90 ° direction to be peeled off, and the number of crosses not peeled out of the 100 crosses was evaluated.

Peel strength A coating film was prepared on a base material, a cut was made with a cutter blade at a width of 1 cm until the blade reached the base material, and the end portion was peeled off.
180 at the speed of 50 mm / min.
The peel strength was measured by pulling in the ° direction.

Water resistance test The test piece was immersed in water at 40 ° C. for 240 hours, and then a cross- cut test and a peeling test were performed.

(Example 1) (Maleic anhydride-modified copolymer) Propylene / butene (70/3) having an intrinsic viscosity [η] of 1.29 dl / g.
0 mol ratio) 100 g of copolymer, 5 g of maleic anhydride,
0.35 g of 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne-3 (manufactured by NOF CORPORATION, Perhexin 25B) was mixed in advance with a Henschel mixer,
The obtained mixture is a twin-screw extruder (PC manufactured by Ikegai Tekko KK, PC
M-30), the resin temperature is 250 ° C, the rotation speed is 15
The mixture is heated and kneaded at 0 rpm to carry out a graft copolymerization reaction,
A maleic anhydride-modified copolymer was obtained. The intrinsic viscosity [η] of the obtained maleic anhydride-modified copolymer was 0.73 dl /
The graft amount of g and maleic anhydride was 0.57% by weight.

(Chlorination of Maleic Anhydride Modified Copolymer)
300 g of the maleic anhydride-modified copolymer obtained above
Was completely dissolved in 3 liters of carbon tetrachloride at 73 ° C., and while keeping the temperature, chlorine gas was introduced and reacted for about 4 hours. After the completion of the reaction, a large excess of methanol was added to the reaction mixture to precipitate a polymer, which was separated by filtration, washed repeatedly with acetone, and dried under reduced pressure to obtain a chlorinated modified copolymer. The intrinsic viscosity [η] of the obtained chlorinated modified copolymer was 0.67 dl / g and the degree of chlorination was 17% by weight. This chlorinated modified copolymer is dissolved in toluene to give a solid content of 1
A 5 wt% toluene solution was prepared.

(Coating) The obtained toluene solution of the chlorinated modified copolymer was applied to a square plate of polypropylene (X440: Mitsui Petrochemical Industry Co., Ltd.) whose surface was wiped with isopropyl alcohol as a pretreatment liquid. After spray coating at 200 g / m ² , a top coating material (R-271 manufactured by Nippon Bee Chemical Co., Ltd.) was coated at a dry film thickness of 40 μm to form a coating film. After leaving it at room temperature for 10 minutes,
It was placed in an air oven at 85 ° C. and baked for 30 minutes to prepare a coating film sample. This coating film sample was subjected to a cross-cut test and a peel strength test at the initial stage and after the water resistance test. The results are shown in Table 1.

(Example 2) Using the toluene solution of the chlorinated modified copolymer obtained in Example 1, the topcoat paint was changed to Soflex 1200 manufactured by Kansai Paint Co., Ltd., and the baking condition was 120 ° C. A coating film sample was prepared in the same manner as in Example 1 except that the time was changed to 30 minutes. This coating film sample was subjected to a cross-cut test and a peel strength test at the initial stage and after the water resistance test. The results are shown in Table 1.

(Examples 3 to 5) In each example, Example 1
A coating film sample was prepared in the same manner as in Example 1 except that the chlorinated modified copolymer was prepared by changing various conditions in Example 1 and the pretreatment liquid was also changed to that shown in Table 1. Then, it was subjected to a cross-cut test and a peel strength test at the initial stage and after the water resistance test. The results are shown in Table 1.

(Comparative Example 1) Example 1 was repeated except that the toluene solution of the chlorinated modified copolymer prepared in Example 1 was used and a polypropylene square plate that had been steam washed with 1,1,1-trichloroethane was used. A coating film sample was prepared in the same manner as in No. 1 and subjected to a cross-cut test and a peel strength test after the initial and water resistance tests. The results are shown in Table 1.

Comparative Examples 2 and 3 In each example, Example 1
A chlorinated modified copolymer was prepared by changing the various conditions in Table 1 as shown in Table 1, and the pretreatment liquid for a polypropylene square plate was changed to that shown in Table 1 to prepare a coating film sample. It was produced and subjected to a cross-cut test and a peel strength test after the initial and water resistance tests. The results are shown in Table 1.

[0044]

[0045]

[0046]

[0047]

[0048]

The primer composition of the present invention is
Without steam cleaning with 1-trichloroethane,
It is suitable as a primer because it can be applied to a resin molded product, particularly a molded product of polyolefin such as polypropylene, to obtain a coating film having excellent adhesion to the surface thereof and having sufficient peel strength.

Claims (3)

[Claims] 1. A propylene unit (a) content of 15 to 9
0 mol%, the content of the α-olefin unit (b) having 4 to 6 carbon atoms is 10 to 85 mol% (the total content of (a) and (b) is 100 mol%), and the intrinsic viscosity [ η] is 0.
Graft copolymerization was performed so that an olefin polymer having an amount of 8 to 2.0 dl / g contained 0.1 to 10% by weight of at least one graft copolymerized unit selected from unsaturated carboxylic acids and anhydrides thereof. After that, it will be further chlorinated,
Chlorinated modified copolymer 5 having a chlorine content of 5 to 35% by weight
A primer composition comprising -50% by weight and an organic solvent of 95-50% by weight. 2. A propylene unit (a) content of 15 to 9
0 mol%, the content of the α-olefin unit (b) having 4 to 6 carbon atoms is 10 to 85 mol% (the total content of (a) and (b) is 100 mol%), and the intrinsic viscosity [ η] is 0.
A chlorinated polymer having a chlorine content of 5 to 35% by weight, which is obtained by chlorinating an olefin polymer of 8 to 2.0 dl / g, and at least one selected from unsaturated carboxylic acids and anhydrides thereof. A primer composition comprising 5 to 50% by weight of a chlorinated modified copolymer obtained by graft copolymerization so as to contain 0.1 to 10% by weight of a graft copolymerized unit, and 95 to 50% by weight of an organic solvent. 3. The α-olefin is 1-butene, 1-butene.
Pentene, 4-methyl-1-pentene, 3-methyl-1
-The primer composition according to claim 1 or 2, which is at least one selected from pentene and 1-hexene.