JPS6218434A - Coating composition for polyolefin resin - Google Patents

Abstract

PURPOSE:The titled composition which can give a film excellent in appearance, adhesion, weathering resistance, moisture resistance, solvent resistance, etc., comprising a resin prepared from an acrylic monomer, a chlorinated polydiene and a chlorinated polyolefin and a specified curing agent. CONSTITUTION:30-60pts.wt. hydroxyl group-containing acrylic monomer (e.g., 2-hydroxyethyl acrylate), 30-50pts.wt. chlorinated polydiene (e.g., chlorinated polybutadiene) of a chlorine content of 5-50wt% and 10-40pts.wt. chlorinated polyolefin (e.g., chlorinated PE) of a chlorine content of 10-50wt% are solution- polymerized together in the presence of a polymerization initiator (e.g., benzoyl peroxide) to give a resin. This resin is mixed with a polyisocyanate (e.g., hexamethylene diisocyanate) as a curing agent in an amount to provide 1-2mol of the isocyanate groups per mol of the hydroxyl groups.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Industrial Field of Application The present invention is applicable to the protection or cosmetic use of polyolefin resins, such as polypropylene polymers, ethylene-propylene copolymers, ethylene-propylene-diene copolymers, etc. Regarding the coating composition used for this purpose, more specifically, it can be applied to polyolefin resin sheets and molded objects with a one-coat finish to produce a coating film with excellent appearance, adhesion, weather resistance, moisture resistance, solvent resistance, etc. The present invention relates to a coating composition for a polyolefin resin that provides the following properties.

B. Conventional technology Polyolefin resins have excellent properties such as chemical resistance, ozone resistance, heat resistance, water resistance, and good electrical properties, and are lightweight and inexpensive, so they are used in home appliances and other applications. It is widely used as an industrial material such as automobile parts, and is one of the materials whose demand is most expected to grow in the future. However, despite these characteristics, when it comes to automobile parts, for example, various types of plastics are being used to reduce weight from the perspective of energy conservation, and the amount of plastic used is increasing year by year. Its use is limited to some parts. One of the reasons preventing its widespread use is that polyolefin resins are nonpolar and crystalline, making painting and adhesion extremely difficult. Conventionally, adhesion has been improved by activating the surface of polyolefin resin molded products by plasma treatment or gas flame treatment, but these methods require complicated processes and require large equipment costs and time losses. However, it has the disadvantage that the surface treatment effect varies due to the complexity of the shape of the molded product and the effects of pigments and additives in the resin. Therefore, as a method for painting without these pre-treatments, various primer compositions such as those used in polypropylene bumper painting of automobiles have been recently proposed, but these involve the complexity of a two-coat finish. Coating compositions for one-coat finishing include chlorinated polyolefins and cyclized rubbers that have strong adhesion to polyolefin resins, but are weather and moisture resistant.

It has poor solvent resistance and does not have sufficient coating performance.

To compensate for these shortcomings, attempts have been made to mix chlorinated polyolefins with acrylic resins and alkyd resins, which have good physical properties for paints, but originally acrylic resins and alkyd resins are not chlorinated polyolefins. The compatibility is poor, which causes problems such as a decrease in the gloss of the coating film and a significant deterioration of the appearance.

In order to improve these drawbacks, a coating composition obtained by copolymerizing an acrylic monomer and a chlorinated polyolefin has been proposed, as seen in JP-A-58-71966. However, although these compositions have made some progress compared to systems in which an acrylic resin and a chlorinated polyolefin are mixed, they do not have a satisfactory coating appearance and have the disadvantage that the coating film is brittle.

Problems to be Solved by the C0 Invention In order to solve the above-mentioned problems, the present inventors have developed an acrylic monomer (I) and chlorine chlorinated with a chlorine content in the range of 5 to 50 W%. A coating composition obtained by copolymerizing a chlorinated polydiene (ff) and a chlorinated polyolefin (I [[) with a chlorine content in the range of 10 to 50 w[%] is superior to polyolefin resins. It was discovered that it exhibits adhesion and provides a tough and glossy coating film.
This was already proposed in patent application No. 60-027268. However, this method was somewhat insufficient in terms of weather resistance, moisture resistance, gasoline resistance, etc. under severe conditions required for painted objects used outdoors such as automobiles and motorcycles. The present invention improves these drawbacks.

A means to solve the D1 problem, that is, acrylic monomer (I) and a chlorine content of 5 to 50
Chlorinated polydiene (I[>
A coating composition containing a resin obtained by copolymerizing chlorinated polyolefin (III) with a chlorine content of 10 to 50 wt% as a main ingredient, and a polyisocyanate compound as a curing agent is blended with this resin. The inventors have discovered that the above-mentioned drawbacks can be improved and have come up with the present invention.

The acrylic monomer (I) used in the present invention requires water MW to chemically undergo urethanization with the isocyanate group in the polyisocyanate compound, so the acrylic monomer (I) may be an acrylic monomer containing a hydroxyl group, It is desirable that it is a mixture of an acrylic monomer containing at least a hydroxyl group and an acrylic monomer containing no hydroxyl group. Also, (I) and (
The resin obtained by copolymerizing II) and (III) has a hydroxyl value based on the solid content of 20 or more, preferably 30 to 70. If the hydroxyl value is too low than 20, it will form a bond with the polyisocyanate compound! The density decreases, and the weather resistance, moisture resistance, and gasoline resistance of the coating film decrease. On the other hand, if the hydroxyl value is too high than 80, the solution of the copolymer resin becomes opaque or separates into two layers, resulting in a decrease in the gloss of the coating film. Examples of the acrylic monomer containing a hydroxyl group include 2-hydroxylethyl acrylate, 12-hydroxylethyl methacryl, acrylic Pa2-
Hydroxylpropyl, 2-hydroxylpropyl methacrylate, etc., and examples of acrylic monomers that do not contain hydroxyl groups include acrylic acid, methyl acrylate, ethyl acrylate, n-butyl acrylate, and 2-ethylhexyl acrylate. , lauryl acrylate, glycidyl acrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate.

Examples include glycidyl methacrylate.

The chlorinated polydiene (II) used in the present invention is used in order to impart flexibility to the coating film, as well as acrylic monomer (I> or copolymer and chlorinated polyolefin (I[[)
This is a component for improving mutual compatibility with.

The polydiene referred to in the present invention includes polybutadiene, polypentadiene, polyisoprene, etc. For example, the above-mentioned polybutadiene is a liquid polybutadiene obtained by polymerizing butadiene with a specific catalyst, and has a hydroxyl group or carboxyl group at the end. Also includes Shino with. Other liquid polydienes include liquid rubbers having unsaturated groups such as liquid polychloroprene, liquid polyisoprene, and liquid polypentadiene.

The chlorine content of the chlorinated polydiene is preferably used in the range of 5 to 50% by weight. If the chlorine content is too low, the appearance of the coating film will deteriorate and there is a risk of gelation during the copolymerization reaction. If the chlorine content is too high, chlorinated polyolefin (I[
The compatibility with [) deteriorates, and the reactivity with the acrylic monomer (I>) also decreases.

Chlorination of polydienes can be easily carried out using conventional reaction methods. For example, polybutadiene is dissolved in a chlorinated solvent such as tetracarbon, and heated from room temperature to 120°C under pressure or normal pressure in the absence of a catalyst, in the presence of a catalyst, or under ultraviolet irradiation.
This is done by introducing chlorine gas at a temperature range of .

The chlorinated polyolefin (1 [[) used in the present invention is a component for imparting adhesion to the polyolefin resin to the coating film, and the chlorine content can be used in the range of 10 to 50 wt%, and is preferably is 15~45W [%
It is. If the chlorine content is too low, the state of the solution at low temperatures and the appearance of the coating film will deteriorate. On the other hand, if the chlorine content is too high, the adhesion to polyolefin resins will decrease.

Raw materials for chlorinated polyolefins include crystalline polypropylene and amorphous boria [l-pyrene].

polybutene-1, polypentene-1,4-methylpentene-1, low density or high density polyethylene, ethylene-1
Examples include propylene copolymers and ethylene-bu-O-pyrene-diene copolymers. Furthermore, modified polyolefin resins in which carboxyl groups, hydroxyl groups, etc. are introduced can also be used. The chlorination reaction can be carried out in the same manner as the chlorination of polybutadiene described above, but the reaction temperature is preferably in the range of 50 to 120°C, and the chlorination must be carried out in the presence of a catalyst or under irradiation with ultraviolet rays.

The copolymerization of the acrylic monomer (I), the chlorinated polydiene (II), and the chlorinated polyolefin (III) according to the present invention is carried out by solution polymerization.The solvent used is an aromatic solvent such as toluene or xylene. is most preferable,
In addition, ester solvents, ketone solvents, alcohol solvents, chlorine solvents, aliphatic solvents, cycloaliphatic solvents, etc. may be used in combination. As the polymerization initiator, a peroxide type such as benzoyl peroxide or an azobis type such as azobisisobutyronitrile can be used. Quinones such as hydroquinone may be used as a stopper.

The polymerization method is to dilute the chlorinated polydiene (I) and the chlorinated polyolefin <m> appropriately with a solvent, mix them, add an initiator, heat them, and gradually add the acrylic monomer (I). The basic process is to react while adding (I
), (II), and (II) may be mixed in advance, an initiator may be added, and the mixture may be heated and reacted.

Examples of the polyisocyanate compound used as a curing agent in the present invention include hexamethylene diisocyanate and tolylene diisocyanate (2°4-tolylene diisocyanate, 2,6-tolylene diisocyanate) 4. C
-diphenylmethane diisocyanate, metaxylylene diisocyanate, etc. In addition, organometallic compounds such as zinc octenoate and dibutyltin laurate are used as catalysts, and lead naphthenate, which is an internal curing agent for oxidative polymerization type resins, is used as a catalyst.
Addition of cobalt naphthenate etc. accelerates the curing reaction.

The blending ratio of the acrylic monomer (1), chlorinated polydiene (n), and chlorinated polyolefin (II[) according to the present invention is determined depending on the desired surface hardness, abrasion resistance, surface gloss of the coating film, etc. It may be determined as appropriate, but if it is too large or too small, a well-balanced and good coating film cannot be obtained. That is, (
I) 30-60 weight part, (II) 30-50 + mouth part,
(III) It is preferable to copolymerize with a weight of 10 to 40 suspended parts. In addition, the amount of polyisocyanate I/compound added is suitably 1 to 2 moles of isocyanate groups per 1 mole of hydroxyl groups in the resin solid content obtained by copolymerizing (I) with (It> and (I[[)). It is.

80 Effect The coating composition according to the present invention may be used as a coating as it is, or may be used as a paint by adding a solvent, pigment, or other additives. In addition, although the composition shows well-balanced coating film properties by itself, if necessary, cyclized rubber can be used.
Petroleum resin.

There is no problem in further adding and using coumaron indene resin, chlorinated polyolefin resin, acrylic resin, alkyd resin, etc.

The coating composition according to the present invention is applied to a polyolefin resin sheet or molded article and dried at a temperature between room temperature and 150°C to obtain a cured coating film with a one-coat finish. Got 4! The film has excellent adhesion and provides a much tougher and glossier film than other one-coat finishes used for similar purposes. It has better weather resistance, moisture resistance, water resistance, gasoline resistance, etc. than the coating composition already proposed in No. 60-027268.

Further, the composition of the present invention can be applied not only to polyolefin resins but also to other base materials such as plastics, wood, concrete, etc., and can be used as an undercoat. The top coat used for this removal may be existing paints, such as urethane resin paints or melamine resin paints.

Epoxy resin paints, acrylic resin paints, alkyd resin paints, etc. are suitable.

F. Examples and Effects of the Invention Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited thereto.

Prototype example-1 Nippon Soda Polybutadiene B-3000 (liquid polybutadiene manufactured by Nippon Soda Co., Ltd., number average molecular weight 3000) 5
Pour 005i into a glass-lined reaction pot, and
Carbon tetrachloride was added and dissolved uniformly. Air was completely purged with nitrogen gas, and chlorine gas was introduced from the bottom of the reactor while keeping the temperature at 50°C and irradiating it with ultraviolet light. The chlorine content was 25 wt%. , 30 wt %, and 35 wt % were taken, and carbon tetrachloride was distilled off and replaced with toluene to obtain three types of 1-toluene solutions of chlorinated polybutadiene with a nonvolatile content of 50 W[%].

Prototype example - 2 Isotactic polypropylene 50o LJ with number average molecular weights is, ooo is put into a glass-lined reaction pot, 8 (carbon tetrachloride) is added, temperature is 110℃, pressure is 2 and 9icm is sufficient After dissolving in the solution, chlorine gas and air were introduced from the bottom of the reaction vessel while irradiating ultraviolet rays.Two samples with chlorine content of 27w% and 30vit% were taken out, carbon tetrachloride was distilled off, and replaced with toluene. Non-volatile content is 3
Two kinds of toluene solutions of chlorinated polypropylene of 0 w (%) were obtained.

Prototype Example-3 500 g of maleic anhydride-modified polypropylene with a number average molecular weight of 15,000 and a saponification value of 26 was chlorinated in the same manner as Prototype Example-2 to obtain a chlorine content of 25 W[% and nonvolatile content of 30 wt%]. 45I is a toluene solution of maleic anhydride-modified chlorinated polypropylene.

Example 1 The chlorinated polybutadiene obtained in Prototype Example 1 (chlorine content: 30W (%)) was placed in a flask equipped with a stirrer, a thermometer, and a cooling tube for refluxing the 70ml.

Nonvolatile content 50wt%) 120g, chlorinated polypropylene obtained in Prototype Example-2 (chlorine content 27W [%, nonvolatile content 30wt%) 15J7. 20g of T-roon,
Benzoyl bar Δoxide 1. Add OJ and heat to 85°C
Stir for 30 minutes. Next, methyl methacrylate 26.5
7゜n-butyl methacrylate 3g, methacrylic acid 1g.

A warm mixture of 15.59 g of 2-hydroxyethyl acrylate is added in 2 hours. Three hours after the addition was completed, 0.59 g of benzoyl peroxide was added again, and the mixture was stirred for an additional 3 hours to complete the copolymerization reaction in a total of 8 hours. The resulting composition was a homogeneous, transparent, and viscous liquid with a nonvolatile content of 44.
It was 6wt%.

Next, 100 g of this composition and 28 g of titanium dioxide were dispersed in a sand mill for 3 hours, and then an isocyanate curing agent Coronate El-1 (manufactured by Nippon Polyurethane Industries Co., Ltd.) was used.
7.9'j and 2.79% of 10% zinc octylate solution as accelerator, 13~
Adjust the viscosity with toluene so that it lasts for 15 seconds, and prepare a boria 1] pyrene plate EP-A2 (Mitsui Toatsu Chemical Co., Ltd. ￥i).
spray painted on. After drying at room temperature for about 15 minutes, forced drying at 80° C. for 30 minutes, and standing indoors for one week, the coating film was tested. The results are shown in Table-1.

Example-2 Prototype example-1 is 1! In addition, 90 g of chlorinated polybutadiene (chlorine content 35 wt%, non-volatile content 50 W [%), prototype example -
Chlorinated polypropylene obtained in step 2 (chlorine content 30 wt%
, non-volatile content 30wt%) 150g, toluene 3
5J, benzoyl peroxide 1.5! J, methyl methacrylate 35g, lauryl methacrylate 8.8g,
1 g of methacrylic l'iQ, 2-hydroxylethyl methacrylate5. A copolymerization reaction was carried out according to the reaction method of Example-1 at a blending ratio of fly and acrylic Jl/2-hydroxyethyl acid 10.47. The resulting composition was a homogeneous, transparent, and viscous liquid with a nonvolatile content of 44.9 wj%. Next is this composition 100! ? , titanium dioxide 2
Paint preparation and coating tests were conducted in the same manner as in Example 1 using a blending ratio of 8 g, isocyanate curing agent Coronate L (manufactured by Japan Polyurethane Industries Co., Ltd.) 17.5 g, and 2.7 g of 10% zinc octylate solution. Ta. Display the results -
Shown in 1.

Example-3 120 g of chlorinated polybutadiene obtained in Prototype Example-1 (JN element content 25W [%, non-volatile content 50wt%), JM chlorinated polypropylene obtained in Prototype Example-3 (chlorine content 2
5W (%, nonvolatile content 30wt%) 150g, I
-20g of toluene, 1.5g of benzoyl peroxide,
Methyl methacrylate 23.4! ? , 2-ethylhexyl methacrylate 5.8 g, 2-hydroxyethyl methacrylate 4.4 g, 2-hydroxyethyl acrylate 11
．． A co-merging reaction was carried out according to the reaction method of Example 1 at a blending ratio of 7 g. The obtained composition was a homogeneous, transparent, and viscous liquid, and the nonvolatile content was 44.5 wt%. Next, 100 g of this composition, 28 g of titanium dioxide, 17 g of isocyanate curing agent [RORO-1~L manufactured by Nippon Polyurethane Industries Co., Ltd.], 2.73 g of 10% zinc octylate solution
The coating composition was prepared using the same method as in Example 1, and the film was tested using the same method as in Example 1. The results are shown in Table-1.

Comparative Example-1 JRL X-oxylated polybutadiene obtained in Prototype Example-1 (chlorine content 30W (%, non-volatile content 50wt%) 1209.
15 og of chlorinated polypropylene (chlorine content 27 W [%, non-volatile content 30 W [%]) obtained by 1 q in Prototype Example-2,
l ~ 20g of luene, 1.5 g of penzoyl peroxide
rJ, 36 g of methyl methacrylate, 9 g of n-butyl methacrylate, and the blending ratio of methacrylic M Iy, Example =
A copolymerization reaction was carried out according to the reaction method of 1. The resulting composition was a uniform, transparent, viscous liquid with a non-volatile content of 44
．． It was 7wt%. Next, paint preparation and coating tests were carried out in the same manner as in Example-1 using a blending ratio of 100 g of this composition and 28 g of titanium dioxide. The results are shown in Table-1.

Comparative Example-2 In Actual Example-1 (q) Chlorinated polybutadiene (chlorine content 35 wt%, non-volatile content 50 W [%) 90 g, prototype example-
1q of chlorinated polypropylene (chlorine content test method Adhesion: Make 100 gobbles on the painted surface that reach the substrate at 1#lII intervals, stick cellophane adhesive tape on top of it, and pull it in a 180° direction. After peeling off, judgment was made based on the extent to which the coating film remained.

Accelerated weathering: A force-bond arc sunshine weather meter was used. Glossiness was measured using a 60'' specular reflection, and whiteness was measured using a Hunter.

Moist water resistance: The coated board was immersed in warm water at 40°C for 120 hours and 240 hours, and the state of the coating film was examined.

Gasoline resistance: Soak absorbent cotton in Nisseki regular gasoline and coat the coated surface with
The coating was rubbed 0 times and the state of the coating film was examined.

Methanol resistance: Absorbent cotton was impregnated with methanol and the coated surface was rubbed 100 times to examine the condition of the coated film.

The binding in Table 1 shows that the compositions of Examples 1 and 2.3 are the same as those of Comparative Example 1.
2. Long-term weather resistance compared to 3.

This shows that it has excellent gasoline resistance in addition to water resistance. That is, it can be seen that the product of the present invention improves the drawbacks of the composition already proposed in Japanese Patent Application No. 60-027268.

1E Kōro - (voluntary) 1985 1
October 17 old + l'i',
``'Detailed description of the invention in the specification

Claims (2)

[Claims] (1) Acrylic monomer (I) and chlorine content between 5 and 5
Chlorinated polydiene (II) chlorinated in the range of 0 wt%
The main ingredient is a resin obtained by copolymerizing chlorinated polyolefin (III) with a chlorine content in the range of 10 to 50 wt%, and a polyisocyanate compound is blended therein as a curing agent. Coating composition. (2) A patent in which the acrylic monomer (I) is an acrylic monomer containing a hydroxyl group, or a mixture of an acrylic monomer containing a hydroxyl group and an acrylic monomer not containing a hydroxyl group A coating composition according to claim 1.