JP3514411B2 - Method for producing binder resin composition for base coat - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a polyolefin resin such as polypropylene, polyethylene and ethylene-based resin.
TECHNICAL FIELD The present invention relates to a binder resin composition for a base coat used for the purpose of protecting or making cosmetics such as a propylene copolymer and an ethylene-propylene-diene copolymer, and more specifically, a binder for a base coat when performing a metallic coating of a polyolefin resin molded product. It relates to a resin composition.

[0002]

2. Description of the Related Art Plastics have many advantages such as high productivity, wide design freedom, light weight, rust prevention and impact resistance. It is often used as a material for
In particular, polyolefin resin is cheap and moldable,
Since it has many excellent properties such as chemical resistance, heat resistance, water resistance, and good electrical properties, it is widely used as an industrial material and is one of the materials that are expected to grow in demand in the future. is there. However, unlike polyolefin-based synthetic resins such as polyurethane-based resins, polyamide-based resins, acrylic-based resins, polyester-based resins, etc., polyolefin-based resins are non-polar and crystalline, which makes them difficult to coat and bond. Have.

Chlorinated polyolefins, which have a strong adhesion to polyolefin resins, have been conventionally used as binder resins for coating and adhering such polyolefin resins having poor adhesion.

When a polyolefin resin molding is metallically coated, generally, a chlorinated polyolefin primer composition is coated on the molding, a base coat is then coated, and a clear coat is further coated. 3 coat method is adopted. It is possible to simplify the work and reduce the cost by applying the so-called 2-coat method of applying the clear coat after applying the base coat of the chlorinated polyolefin resin, but since the chlorinated polyolefin has poor resistance to heat and ultraviolet rays, When the coating method is applied, problems such as deterioration of the chlorinated polyolefin due to heat applied through the clear coat and ultraviolet rays occur.

Since the chlorinated polyolefin has poor resistance to heat and ultraviolet rays as described above, an epoxy compound having a glycidyl group is generally added and used as a stabilizer. However, only by adding the epoxy compound, the effect of the stabilizer becomes insufficient because the epoxy compound migrates out of the system with the lapse of time after forming the coating film.

In order to prevent migration of the epoxy compound, a method of reacting the epoxy compound with a chlorinated polyolefin can be considered. Examples of primer compositions and coating compositions obtained by adding an epoxy compound to a chlorinated polyolefin and reacting it include, for example, JP-B-63-50381 and JP-B-1-164.
14 and JP-A-8-100032.
These are carboxyl group-containing chlorinated polyolefins obtained by graft-copolymerizing an unsaturated carboxylic acid or an anhydride thereof with a polyolefin, and then adding an epoxy compound to the polyolefin-based resin molded product, and then coating the carboxyl group and the epoxy compound. Or a reaction of the carboxyl group with an epoxy compound in the presence of a catalyst such as a tertiary amine compound or a tin compound in advance and then coating.

However, among these compositions, those to which epoxy is added are inferior in reactivity between the carboxyl group and the epoxy compound, so that the epoxy compound easily migrates out of the system with the passage of time and is stable to heat and ultraviolet rays. Sex becomes insufficient. On the other hand, the one in which the carboxyl group and the epoxy compound are previously reacted in the presence of a catalyst such as a tertiary amine compound or a tin-based compound and then coated is a polyolefin-based resin because the carboxyl group and the epoxy compound cause a crosslinking reaction. Adhesion to the resin molded product deteriorates.

[0008]

SUMMARY OF THE INVENTION In the present invention, when a polyolefin resin molded product is metallically coated, even if it is coated with two coats, a base coat and a clear coat, adhesion, moisture resistance, heat stability and resistance It is intended to provide a binder resin for a base coat, which has various physical properties such as an ultraviolet property.

[0009]

The method for producing a binder resin composition for a base coat according to the present invention which solves the above-mentioned problems, has a content of (a) a carboxyl group or an acid anhydride group of 1 to
Carboxyl group with 10% by weight and chlorine content of 5 to 50% by weight
Alternatively , (b) a monomer 1 having an ethylenically unsaturated bond and a glycidyl group in the acid anhydride group- containing chlorinated polyolefin.
A binder resin composition for a base coat, which comprises graft-copolymerizing about 20% by weight in the presence of a radical generator.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The carboxyl group-containing chlorinated polyolefin (a) used in the present invention can be easily produced by using a known method. For example, a polyolefin is heat-melted and, if necessary, is thermally decomposed to reduce its viscosity or to reduce the unsaturated carboxylic acid monomer of a carboxylic acid or a carboxylic acid anhydride in the presence of a radical generator in a batch system or a continuous system. ~ 10 wt% after graft polymerization, dispersed or dissolved in a medium such as water or carbon tetrachloride or chloroform,
It can be obtained by blowing chlorine gas in the temperature range of 50 to 120 ° C. under pressure or normal pressure under irradiation of a radical generating catalyst or ultraviolet rays to cause a reaction.

It can also be obtained by previously chlorinating the polyolefin by the above method and then graft-copolymerizing a carboxylic acid or a carboxylic anhydride in the presence of a radical generator.

As the raw material polyolefin, crystalline polypropylene, amorphous polypropylene, propylene-α
-Olefin copolymers and the like can be used alone or in combination of two or more, but from the viewpoint of workability and adhesiveness of the primer composition, crystalline polypropylene having a weight average molecular weight of 10,000 to 70,000, or a weight average molecular weight of 10,000 to A propylene-α-olefin copolymer containing 70,000 and a propylene component in an amount of 50 to 97 mol%, and the α-olefin unit is, for example, ethylene, 1-butene, 1-pentene or 4-methyl-1. At least one kind of α-olefin having 2 or 4 to 6 carbon atoms selected from -pentene, 3-methyl-1-pentene and 1-hexene is preferable.

The weight average molecular weight of the raw material polyolefin is 1
If it is less than 0,000 or the propylene component is less than 50 mol%, the adhesion to the polyolefin resin will be poor, and if the weight average molecular weight exceeds 70,000, the primer will not be atomized when coating with air spray etc. It is not preferable because the aesthetics of the work surface are impaired. Also, propylene-α-
If the α-olefin of the olefin copolymer has more than 6 carbon atoms, the adhesion to the polypropylene resin becomes poor.

Examples of unsaturated carboxylic acid monomers for introducing a carboxyl group include acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid, itaconic anhydride, aconitic acid and aconitic anhydride. The graft copolymerization amount is preferably 1 to 10% by weight with respect to the polyolefin. If it is less than 1%, the adhesion to the top coat will be poor, and if it exceeds 10%, the adhesion to the polyolefin resin will be poor.

The radical generator used in the graft copolymerization reaction includes, for example, di-tert-butyl peroxide, tert-butyl hydroperoxide, dicumyl peroxide, benzoyl peroxide, tert-butyl peroxide benzoate and methyl ethyl ketone. Peroxides, peroxides such as di-tert-butyldiperphthalate and azonitriles such as azobisisobutyronitrile.

The binder resin composition for a base coat of the present invention preferably contains 1 to 20% by weight of the monomer (b) having an ethylenically unsaturated bond and a glycidyl group, based on the above-mentioned carboxyl group-containing chlorinated polyolefin (a). Is obtained by 3 to 15% by weight graft copolymerization.
When the amount of the monomer (b) is less than 1% by weight, the heat resistance and the ultraviolet resistance are deteriorated, which is not preferable. On the other hand, if it is more than 20% by weight, the binder resin solution thickens or gels during storage, which is not preferable.

The graft copolymerization is carried out by appropriately diluting the carboxyl group-containing chlorinated polyolefin (a) with a solvent, then heating it, adding the above-mentioned radical generator, and then gradually adding the monomer (b). Although the reaction is a basic process, the reaction may be performed by previously mixing (a) and (b), adding a radical generator and then heating.

The solvent used in the reaction is preferably an aromatic solvent such as toluene or xylene, and also an ester solvent such as ethyl acetate or butyl acetate, a ketone solvent such as methyl ethyl ketone or methyl isobutyl ketone, n-hexane,
Aliphatic solvents such as heptane and cycloaliphatic solvents such as cyclohexane, methylcyclohexane and ethylcyclohexane may be used in combination. In addition, alcohol solvents such as methanol, ethanol, isopropanol, n-butanol, propylene glycol methyl ether,
2 to the reaction solution after the reaction with ethylene glycol ether solvent such as propylene glycol ethyl ether
By adding 10% by weight, the storage stability of the binder resin solution can be improved.

The monomer (b) having an ethylenically unsaturated bond and a glycidyl group as used in the present invention includes, for example, allyl glycidyl ether, glycidyl acrylate, glycidyl methacrylate and the like. Any monomer containing individual can be used.

The binder resin composition of the present invention is mixed with an aluminum paste and a coloring pigment, and if necessary, other additives such as an ultraviolet absorber, an antioxidant and a pigment settling agent, and kneaded to obtain a metallic composition. A specific base coat can be manufactured. Further, the binder resin shows a balanced coating property by itself, but if necessary, an alkyd resin, an acrylic resin, a polyacrylic polyol, a polyester resin, a polyester polyol, a polyether resin, a polyether polyol, a polyurethane resin. It does not matter if an epoxy resin or the like is added and used.

A feature of the present invention is that a polyolefin having a carboxyl group-containing chlorinated polyolefin (a) is graft-copolymerized with a monomer having an ethylenically unsaturated bond and a glycidyl group in the presence of a radical generator to give a polyolefin. The purpose of the present invention is to obtain a binder resin for a base coat, which has various physical properties such as thermal stability and ultraviolet resistance as well as adhesion and moisture resistance to a resin molded product.

That is, the chlorinated polyolefin in the carboxyl group-containing chlorinated polyolefin (a) component is a component that adheres to the polyolefin resin molded product, and the graft-copolymerized carboxyl group is a clear coat used for top coating. It is a component that adheres to. The monomer having an unsaturated bond and a glycidyl group graft-copolymerized with the component (a) is a component that imparts thermal stability and UV resistance to the chlorinated polyolefin. The effect of the glycidyl group to give the chlorinated polyolefin thermal stability and UV resistance is as follows: When heat or UV rays act on the chlorinated polyolefin, the hydrochloric acid liberated from the chlorinated polyolefin becomes glycidyl group. Is believed to be accepted and stabilized.

[0023]

Of course, even if an epoxy compound having a glycidyl group is added to the chlorinated polyolefin, the thermal stability and the UV resistance are improved, but the migration of the epoxy compound from the chlorinated polyolefin or the chlorinated polyolefin and the epoxy compound are uniform. In the long term, the thermal stability and the UV resistance are impaired due to the fact that they are not compatible with. Further, the above-mentioned drawbacks are improved by preliminarily reacting the carboxyl group in the carboxyl-containing chlorinated polyolefin and the glycidyl group in the epoxy compound in the presence of a catalyst such as a tertiary amine compound or a tin compound to copolymerize them. Although it is possible to do so, there is a drawback in that the adhesion with the polyolefin resin molded product is deteriorated because the carboxyl group and the epoxy compound undergo a crosslinking reaction to form a three-dimensional structure.

In the case of the present invention, a monomer having an ethylenically unsaturated bond such as glycidyl methacrylate and a glycidyl group is added to a carboxyl group-containing chlorinated polyolefin,
Since the graft copolymerization is carried out in the presence of the radical generator, there is an advantage that the formation of the above-mentioned three-dimensional structure is suppressed and the adhesiveness to the polyolefin resin molded product is not impaired.
That is, a hydrogen radical or a chlorine radical is extracted from a carboxyl group-containing chlorinated polyolefin by the action of a radical generator, a radical is generated on the main chain of the chlorinated polyolefin, and then a monomer having an ethylenically unsaturated bond is mainly formed. This is because the graft copolymerization is performed by a so-called radical reaction that reacts with radicals on the chain.

[0026]

EXAMPLES The present invention will be specifically described below with reference to examples.

(Production Example-1) 5 kg of crystalline polypropylene having a weight average molecular weight of 40,000 was placed in a three-necked flask equipped with a stirrer, a dropping funnel, and a cooling tube for refluxing the monomer, and kept constant at 180 ° C. It melted completely in a hot water bath. The inside of the flask was replaced with nitrogen, and 200 g of maleic anhydride was added while stirring for about 5 minutes, then 20 g of di-t-butyl peroxide was dissolved in 50 ml of heptane and the mixture was added from the dropping funnel over about 30 minutes. I put it in. At this time, the inside of the system was kept at 180 ° C., and after continuing the reaction for further 15 minutes, unreacted maleic anhydride was removed over about 30 minutes while depressurizing the inside of the flask with an aspirator. The product was then charged to a glass lined reaction kettle and
Add 1 liter of chloroform under pressure of ² kg / cm ^2.
After sufficiently dissolving at 100 ° C, chlorine gas is blown from the bottom of the reaction vessel while irradiating with ultraviolet rays, chlorination reaction is performed until the chlorine content becomes 22% by weight, and the solvent chloroform is distilled off with an evaporator and replaced with toluene. The chlorinated polypropylene containing carboxyl groups (A
-1) was obtained. Next, 1 kg of this (A-1) was placed in a three-necked flask equipped with a stirrer, a dropping funnel, and a cooling tube for refluxing the monomer, and the inside of the flask was replaced with nitrogen.
3 g of benzoyl peroxide was added with stirring at ℃, and stirred for about 30 minutes. Then glycidyl methacrylate
40 g was added from a dropping funnel over about 60 minutes, and after reacting for 3 hours, the concentration was adjusted, and a carboxyl group-containing chlorinated polypropylene graft-copolymerized with a monomer having an ethylenically unsaturated bond (chlorine content: 19.2 %, Solid content 30%) to obtain a toluene solution (A-2).

(Production Example-2) Propylene-butene-ethylene copolymer (propylene-α-olefin copolymer) having a weight average molecular weight of 60,000 and a propylene component of 68 mol%.
5 kg was placed in a three-necked flask equipped with a stirrer, a dropping funnel, and a cooling tube for refluxing the monomer, and completely melted in a hot water bath kept at 180 ° C. The inside of the flask was replaced with nitrogen, 300 g of maleic anhydride was added over about 5 minutes while stirring, and then 30 g of dicumylperoxide was added.
Was dissolved in 50 ml of heptane and charged from a dropping funnel over about 30 minutes. At this time, the temperature inside the system is maintained at 180 ° C, and
After continuing the reaction for a minute, the unreacted maleic anhydride was removed over about 30 minutes while depressurizing the inside of the flask with an aspirator. The product is then placed in a glass lined reaction kettle, 80 liters of chloroform are added and 2
After fully dissolving at 100 ° C under a pressure of kg / cm ² , chlorine gas is blown from the bottom of the reaction vessel while irradiating with ultraviolet rays, and the chlorination reaction is performed until the chlorine content becomes 18% by weight, and the solvent chloroform is added. It was distilled off with an evaporator and replaced with toluene to obtain a carboxyl group-containing chlorinated polyolefin (B-1) in a toluene solution with a solid content of 30%. Next, this (B-
1) 1 kg was placed in a three-necked flask equipped with a stirrer, a dropping funnel, and a cooling tube for refluxing the monomer, the inside of the flask was replaced with nitrogen, and 3 g of benzoyl peroxide was added while stirring at 90 ° C. Stir for minutes. Next, 30 g of glycidyl acrylate was added from a dropping funnel over about 60 minutes, and after reacting for 3 hours, the concentration was adjusted, and a carboxyl group-containing chlorinated polyolefin (chlorine-containing polyolefin having a monomer having an ethylenically unsaturated bond graft-copolymerized Content: 16.2%, solid content 30%) in toluene solution (B-
2) was obtained.

(Production Example-3) 5 kg of crystalline polypropylene having a weight average molecular weight of 50,000 was placed in a glass-lined reaction kettle, and 80 liters of chloroform were added,
After sufficiently dissolving at 100 ° C under a pressure of ² kg / cm ² , chlorine gas was blown from the bottom of the reaction vessel while irradiating with ultraviolet rays, and the chlorination reaction was performed until the chlorine content became 27% by weight, and the solvent chloroform was added. It was distilled off with an evaporator and replaced with toluene to obtain a toluene solution of chlorinated polypropylene having a solid content of 30% by weight. Next, 1 kg of this chlorinated polypropylene was put into a three-necked flask equipped with a stirrer, a dropping funnel, and a cooling tube for refluxing the monomer, the inside of the flask was replaced with nitrogen, and 3 g of benzoyl peroxide was added while stirring at 90 ° C. The mixture was stirred for about 30 minutes. Next, 15 g of methacrylic acid
Was added from the dropping funnel over about 30 minutes, and after reacting for 3 hours, the concentration was adjusted and a carboxyl group-containing chlorinated polypropylene (chlorine content: 25.4% by weight, solid content: 30% by weight) toluene solution (C- 1) was obtained. Next, add 1.5 g of benzoyl peroxide again, stir for about 30 minutes, add 20 g of allyl glycidyl ether from the dropping funnel over about 60 minutes, react for another 3 hours, and then adjust the concentration to remove ethylenic unsaturated bonds. Carboxylic group-containing chlorinated polypropylene graft-copolymerized with the monomer (toluene content: 23.8%, solid content 30%) in toluene (C-
2) was obtained. Table 1 shows the contents of the compositions obtained in Production Examples 1 to 3.

[0030]

[Table 1]

(Example-1) 100 g of (A- 2 ) obtained in Production Example-1 and 43 of cyclohexane
g, isopropanol 7 g, and aluminum paste 3 g were mixed, and the viscosity was adjusted with toluene in a Ford cup # 4 to 13 to 14 seconds / 20 ° C., and spray-painted on a polypropylene plate washed with water to a film thickness of 10 μm. . After a few minutes,
Clear paint (two-component curing type urethane paint) with a film thickness of 30 ~
It was spray-coated so as to have a thickness of 40 μm, dried at room temperature for about 15 minutes, forcedly dried at 80 ° C. for 30 minutes, and allowed to stand at room temperature for another day, and then the coating film was tested. Table 2 shows the composition of the base coat
The test results of the coating film are shown in Table 3.

(Examples 2 and 3) Based on the formulation table shown in Table 2, a base coat was prepared in the same manner as in Example 1 and the coating film was tested. The results are shown in Table 3.

(Comparative Example-1) Obtained in Production Example-3 (C-
1) 100 g, bisphenol A glycidyl ether as a stabilizer (epoxy resin, epoxy equivalent: 184 to 194) 3
g, 1.8-diazo-bicyclo-undecene-7 (tertiary amine-based catalyst) 0.5 g, cyclohexane 50 g, and aluminum paste 3 g were mixed, and a base coat was prepared in the same manner as in Example-1 to test the coating film. I went. The base coat formulation is shown in Table 2 and the coating film test results are shown in Table 3.

(Comparative Example-2) Obtained in Production Example-2 (B-
1) 100 g, trimethylolpropane polyglycidyl ether (epoxy resin, epoxy equivalent: 135-150) 2.3
g, and 1.8 g of 1.8-diazo-bicyclo-undecene-7 (tertiary amine catalyst) were mixed and stirred at 85 ° C. for 5 hours to react. Next, a base coat was prepared from this reaction product by the same method as in Production Example-1 and the coating film was tested. The base coat formulation is shown in Table 2 and the coating film test results are shown in Table 3.

(Comparative Example-3) Obtained in Production Example-1 (A-
1) 100 g, sorbitan polyglycidyl ether (epoxy resin, epoxy equivalent: 179) 2.8 g, and 2-ethylhexyl tin (tin catalyst) 0.15 g were mixed and stirred at 80 ° C. for 8 hours to react. Next, a base coat was prepared from this reaction product by the same method as in Production Example-1 and the coating film was tested. The base coat formulation is shown in Table 2 and the coating film test results are shown in Table 3.

[0036]

[Table 2]

[0037]

[Table 3]

(Film coating test method) ○ UV resistance QUV accelerated weathering tester (manufactured by The Q-Panel Company, USA)
A coating film plate was set on the plate, irradiated with ultraviolet rays, and the adhesiveness was measured at each elapsed time. The method of adhesion test is to make 100 squares on the coated surface that reach the substrate at 1mm intervals, and then adhere cellophane adhesive tape to it and peel it off in 180 ° direction.
The degree of adhesion was determined.

[0039] The coated plate was set in a blast dryer whose heat resistance was adjusted to 60 ° C, and the adhesiveness was measured at each elapsed time. The adhesion test method is the same as for UV resistance.

○ Scratch (marked with X) which reaches the base material was put on the gasoline resistant coating surface, and it was judged by the time until it was immersed in gasoline and the coating film peeled off.

○ Hot water resistance The coated plate was immersed in hot water of 40 ° C for 240 hours to examine the state of the coating film. Also, put a scratch (x mark) that reaches the base material on the coated surface, and stick cellophane adhesive tape on it and 180 °
Then, the adhesion of the coating film peeled off in the direction was examined.

○ Moisture resistance The film was allowed to stand for 240 hours in an atmosphere of 50 ° C. and 98% relative humidity, and the state and adhesion of the coating film were examined by the same method as for hot water resistance.

[0043]

EFFECTS OF THE INVENTION From the results shown in Table 3, as in Examples -1 to 3, a carboxyl group-containing chlorinated polyolefin obtained by graft-copolymerizing a monomer having an ethylenically unsaturated bond in the presence of a radical generator was used as a binder. The base coat used as a resin is obtained by adding an epoxy compound containing a glycidyl group and a tertiary amine-based catalyst to a carboxyl group-containing chlorinated polyolefin as in Comparative Example-1, and as in Comparative Examples-2 and 3. Compared to those obtained by reacting a carboxyl group and a glycidyl group in the presence of a tertiary amine-based catalyst or a tin-based catalyst in advance, it is superior in ultraviolet resistance, heat resistance, gasoline resistance, hot water resistance, and humidity resistance. It can be seen that the binder resin composition for base coat obtained by the production method of the invention is useful for polyolefin resin molded products.

   ─────────────────────────────────────────────────── ─── Continued front page       (56) References JP-A-8-199036 (JP, A)                 JP-A-57-28123 (JP, A)                 JP-A-48-102892 (JP, A)                 JP-A-9-143422 (JP, A)                 International Publication 96/4344 (WO, A1)

Claims (2)

(57) [Claims] 1. (a)Weight average molecular weight 10,000 to 70,000
Crystalline polypropylene, or having a weight average molecular weight of 10,000
~ 70,000 and 50-97 mol% propylene component
A propylene-α-olefin copolymer, which is α-olefin
The number of carbon atoms in the reffin is 2 or 4 to 6Raw material polyolefin
In theCarboxylic acid or carbohydrate to the polyolefin
1-10% by weight of unsaturated carboxylic acid monomer of acid anhydride
After graft copolymerization, chlorine content up to 5-50% by weight
Obtained by chlorinationCarboxyl group-containing chlorinated polyolefin
finAgainst (B) a model having an ethylenically unsaturated bond and a glycidyl group
1 to 20% by weight of nomer in the presence of a radical generator.
Graft copolymer obtained by raft copolymerizationConsists ofBe
Binder resin composition for scorts. 2. (a)Weight average molecular weight 10,000 to 70,000
Crystalline polypropylene, or having a weight average molecular weight of 10,000
~ 70,000 and 50-97 mol% propylene component
A propylene-α-olefin copolymer, which is α-olefin
The number of carbon atoms in the reffin is 2 or 4 to 6Raw material polyolefin
InIs obtained by chlorinating to a chlorine content of 5 to 50% by weight.
Chlorinated polyolefin with carboxylic acid or carboxylic acid
Anhydrous unsaturated carboxylic acid monomer as raw material
1 to 10% by weight based on graft copolymerizationCal
Chlorinated polyolefin containing voxyl groupAgainst (B) a model having an ethylenically unsaturated bond and a glycidyl group
1 to 20% by weight of nomer in the presence of a radical generator.
Graft copolymer obtained by raft copolymerizationConsists ofBe
Binder resin composition for scorts.