JP2001106746A - Modifier for polyolefin-based resin, polyolefin-based composition, and its molded product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a modifier for a polyolefin-based resin which becomes a raw material for preparing a polyolefin-based composition capable of forming a resin layer excellent in adhesion to both a substrate and a coating on the surface of the substrate without surface treatment of the polyolefin-based resin or the like as the substrate and without impairing the mechanical properties. SOLUTION: The modifier for a polyolefin-based resin is obtained by copolymerizing (a) a polyolefin-based homopolymer and/or copolymer which has at least one radical-polymerizable unsaturated double bond as an end- modifying group with (b) an alkyl (meth)acrylate and (c) a polymerizable monomer having at least one kind selected from the group consisting of the carboxy group, hydroxy group, amino group, amide group, cyano group, epoxy group and isocyanate group.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyolefin composition used for changing the surface properties of a plastic and improving its coating properties, and a polyolefin resin used for preparing the polyolefin composition. The present invention relates to a modifier and a molded article in which a coating layer of a polyolefin composition is formed on a substrate.

[0002]

2. Description of the Related Art In recent years, plastics have been used in various industrial fields, and at the same time, awareness of environmental problems relating to plastics, including the recent problem of industrial waste, has been increasing.

Under such circumstances, for example, environmentally-friendly polyolefin-based resins are also attracting attention as non-polyvinyl chloride materials in consideration of recyclability, and are used for food packaging, agriculture, medical use, industrial materials, and miscellaneous goods. And so on.

[0004] For example, polypropylene resin has been used for front ends and rear ends of large parts of automobiles, bumpers and the like. In particular, urethane elastomers have been used for bumpers that require resilience, but due to the demand for weight reduction and recyclability,
Polypropylene (PP) is being used. Since the PP resin is used for such applications, it is naturally required to have various colors, and in many cases, it is necessary to form a coating film on the surface.

However, polyolefin resins such as PP resins have no polar groups in the molecule, unlike polyvinyl chloride. As a result, for example, the surface free energy is low, the adhesion or adhesion to the coating film is low, and the paintability is poor.

[0006] Therefore, some pre-treatment is required in order to coat the surface of the polypropylene resin, and a primer treatment mainly using chlorinated polypropylene (C1-PP) has heretofore been performed. That is, the primer is applied for the purpose of improving the adhesion between the substrate and the coating film.

However, by performing the primer treatment, the number of pretreatment steps increases, and since a solvent is used in this primer treatment, problems such as environmental pollution are likely to occur. Therefore, a member that can perform primerless coating if possible is preferable.

Accordingly, various studies have been conducted to obtain a primerless member since the early 90's. As a method of obtaining a primer-less member, for example, a method of improving the coating film adhesion by modifying the material polypropylene by some method, a method of treating the surface layer with oxygen plasma,
A flame treatment method of irradiating a flame to the surface may be used.

Both methods are excellent in that the coating film adhesion is improved. However, such a method has a problem that, although the environmental pollution is small, the capital investment is large, the processing conditions cannot be made uniform, and the number of processing steps is increased to increase the cost.

Japanese Patent Application Laid-Open No. 9-263657 discloses a method of using a thermoplastic resin composition comprising a compound having a hydroxyl group in order to realize a primerless resin. However, even when a thermoplastic resin composition having a hydroxyl group is used, there has been a problem that sufficient coating film adhesion may not be obtained or mechanical properties may be reduced depending on molding conditions and the like.

[0011]

DISCLOSURE OF THE INVENTION In view of the above, the present invention provides a method of forming a base material on a surface of a base material without subjecting a polyolefin resin or the like to surface treatment and without impairing mechanical properties. And a polyolefin-based composition capable of forming a resin layer having excellent adhesion to a coating film, a polyolefin-based resin modifier as a raw material for preparing the polyolefin-based composition, and a blow molding method or injection An object of the present invention is to provide a molded article in which a coating layer of the polyolefin composition is provided on the surface of a substrate by a molding method.

[0012]

The polyolefin resin modifier of the present invention comprises a polyolefin homopolymer and / or copolymer (a) having a terminal modified with a radically polymerizable unsaturated double bond. And a (meth) acrylic acid alkyl ester (b) and a polymerizable polymer having at least one functional group selected from the group consisting of a carboxyl group, a hydroxyl group, an amino group, an amide group, a cyano group, an epoxy group, and an isocyanate group. It is characterized by being copolymerized with the monomer (c). Hereinafter, the present invention will be described in detail.

The polyolefin homopolymer and / or copolymer (a) whose terminal is modified with the above-mentioned radical polymerizable unsaturated double bond (hereinafter referred to as polyolefin homopolymer and / or copolymer (a)) ) Is not particularly limited, and examples thereof include polyethylene, polypropylene, and ethylene / butylene copolymer.

The group having a radically polymerizable unsaturated double bond existing at the terminal of the polyolefin homopolymer and / or copolymer (a) is not particularly limited. (Meth) acryloyl group, allyl group and the like. In the present invention, the (meth) acryloyl group is a general term for an acryloyl group and a methacryloyl group.

Further, specific examples of the polyolefin-based homopolymer and / or copolymer (a) include, for example, Shell Chemical Comp. In which the terminal of ethylene / butylene copolymer is modified with methyl methacrylate.
"KRATONLIQUID Polym"
er L-1253 ", JP-A-5-194631, JP-A-5-247119, JP-A-6-328
No. 47, JP-A-7-2928 and the like, the terminal of the polypropylene or ethylene / propylene random copolymer is (meth) such as methacrylic acid methyl ester.
Examples include compounds modified with acrylate. These may be used alone or in combination of two or more. Among them, L-1253 and the like are preferable.

The copolymerization ratio of the above-mentioned polyolefin homopolymer and / or copolymer (a) depends on the polyolefin homopolymer and / or copolymer (a) in the total polymerizable composition.
Is preferably an amount that results in a content of 2 to 80% by weight.

If the content is less than 2% by weight, the base material may not have a sufficient fusion force with the polyolefin-based composition base material, while if it exceeds 80% by weight, the polyolefin-based composition The product may not adhere to the coating film, adversely affect the moldability, or adversely affect mechanical properties, particularly rigidity.

The alkyl (meth) acrylate (b) is not particularly restricted but includes, for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-
Propyl (meth) acrylate, isopropyl (meth)
Acrylate, n-butyl (meth) acrylate, se
c-butyl (meth) acrylate, cyclohexyl methacrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isononyl (meth) acrylate, lauryl (meth) acrylate, and the like. The alkyl (meth) acrylates may be used alone or in combination of two or more. Among the above (meth) acrylic acid alkyl esters (b), 4-hydroxybutyl acrylate is more effective in improving the adhesion of the coating film.

The copolymerization ratio of the (meth) acrylic acid alkyl ester (b) is such that the content of the (meth) acrylic acid alkyl ester (b) in the total polymerizable composition is 20.
An amount of up to 50% by weight is preferred.

The carboxyl group, hydroxyl group, amino group,
The polymerizable monomer (c) having at least one functional group selected from the group consisting of an amide group, a cyano group, an epoxy group, and an isocyanate group is not particularly limited, and examples thereof include a compound having a carboxyl group, and a hydroxyl group. A compound having an amino group, a compound having an amide group, a compound having a cyano group, a compound having an epoxy group, a compound having an isocyanate group, and the like.

Examples of the compound having a carboxyl group include (meth) acrylic acid, itaconic acid, crotonic acid, maleic anhydride (anhydride), fumaric acid (anhydride), and carboxyethyl acrylate.

Examples of the compound having a hydroxyl group include 2-hydroxyethyl (meth) acrylate, hydroxypropyl acrylate, 4-hydroxybutyl acrylate, caprolactone-modified (meth) acrylate, and polyoxyethylene oxide-modified (meth) acrylate. (Meth) acrylate and the like.

Examples of the compound having an amino group include dimethylaminomethyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylate, and diethylaminoethyl (meth) acrylate.

Examples of the compound having an amide group include (meth) acrylamide, dimethylaminomethyl (meth) acrylamide, dimethyl (meth) acrylamide, N-methylol (meth) acrylamide, N-butoxydimethyl (meth) acrylamide, Dimethylaminopropyl (meth) acrylamide and the like.

Examples of the compound having a cyano group include (meth) acrylonitrile.

Examples of the compound having an epoxy group include glycidyl (meth) acrylate.

Examples of the compound having an isocyanate group include isopropenyl isocyanate and vinyl isocyanate. Any of these compounds described above may be used alone or in combination of two or more.

The copolymerization ratio of the polymerizable monomer (c) is as follows:
It is preferable that the content of the polymerizable monomer (c) in the whole polymerizable composition be 5 to 40% by weight.

In the present invention, another vinyl monomer is copolymerized in order to adjust the physical properties such as the glass transition temperature, the polarity and the fusibility (adhesion) of the resulting polyolefin resin modifier. be able to.

The other vinyl monomer is not particularly restricted but includes, for example, aromatic monomers such as α-methylstyrene, vinyltoluene and styrene; and methyl vinyl ether, ethyl vinyl ether and isobutyl vinyl ether. Vinyl ether monomers; amino groups such as N-vinylpyrrolidone and acryloylmorpholine, amide groups,
A nitrogen-containing vinyl monomer having a group other than a cyano group and an isocyanate group; and vinyl acetate. These may be used alone or in combination of two or more.

The polyolefin resin modifier of the present invention can be produced by a known method such as solution polymerization, bulk polymerization, suspension polymerization, emulsion polymerization and the like. It can be easily produced by performing solution polymerization in a solvent such as

The polyolefin-based resin modifier of the present invention may contain various known additives, for example, tackifiers, plasticizers, and softeners, as long as the object of the invention is not impaired. , A filler, a stabilizer, an antioxidant, a pigment and the like may be added.

The polyolefin resin modifier preferably has a weight average molecular weight of 10,000 to 5,000,000.
When the weight average molecular weight is less than 10,000, the adhesive strength between the polyolefin composition and the coating film using the same may be insufficient, and when it exceeds 5,000,000, the viscosity at the time of production may be too high. is there. More preferably, it is 100,000 to 2,000,000.

The polyolefin resin modifier of the present invention is used not only as a raw material for preparing the polyolefin composition described below, but also as a solution coating method, a coextrusion method, a heat laminating method and the like. By various methods, a layer of the polyolefin resin modifier can be formed on the surface of the base material. The member having a layer of the polyolefin-based resin modifier on this surface has excellent coating film adhesion.

The polyolefin composition of the present invention is characterized by being prepared by extruding and kneading 80 to 20 parts by weight of the polyolefin resin modifier and 20 to 80 parts by weight of the polyolefin resin. .

The above-mentioned polyolefin resin is not particularly restricted but includes, for example, homopolymers or copolymers of α-polyolefins; copolymers of α-polyolefins and dipolyolefins; ethylene or α-polyolefins and unsaturated carboxylic acids. Examples include a copolymer with an ester.

The α-polyolefin is not particularly restricted but includes, for example, propylene, butene, hexene, octene, decene and the like.

The α-polyolefin homopolymer or copolymer is not particularly restricted but includes, for example, polyethylene, polypropylene, ethylene / propylene copolymer,
Copolymers of ethylene and butene-1; copolymers of ethylene and 4-methylpentene-1 and the like.

The copolymer of the α-polyolefin and the dipolyolefin is not particularly limited, and examples thereof include a copolymer of ethylene and butadiene, and a copolymer of propylene and butadiene.

The copolymer of the α-polyolefin and the unsaturated carboxylic acid ester is not particularly restricted but includes, for example, an ethylene / vinyl acetate copolymer. The above polymers may be used alone or in combination of two or more.

Further, as the above polyolefin resin,
Crystalline polypropylene resins generally used for applications such as molding materials can also be used. Examples of such a crystalline polypropylene resin include, in addition to a crystalline propylene homopolymer, a crystalline copolymer of propylene and another α-polyolefin (particularly, a crystalline propylene / ethylene block copolymer). Or a random propylene copolymer). Among these, the most preferable is a crystalline propylene / ethylene block copolymer which is excellent in practical performance in a balance between rigidity and impact resistance.

Among the above crystalline propylene / ethylene block copolymers, the ethylene component content is 3 to 20.
By weight, the melt flow index is 0.1 to 30 g
/ 10 minutes is preferable. More preferably, the density is in the range of 0.89 to 0.91.

In the present invention, a polypropylene resin mixed with an amorphous ethylene / α-polyolefin copolymer at an arbitrary ratio can be used as the polyolefin resin. The amorphous ethylene / α-polyolefin copolymer is not particularly limited, and examples thereof include ethylene / propylene copolymer rubber, ethylene / propylene / diene copolymer rubber, and ethylene / butene-1 copolymer rubber. Can be

The amorphous ethylene / α-polyolefin copolymer may be modified in advance with an unsaturated organic acid or a derivative thereof. When such a copolymer is contained in a polyolefin-based composition, it is possible to improve the impact strength, reduce the amount of molding warpage, reduce the amount of reheating molding warpage, improve dimensional accuracy, and the like.

The mixing ratio of the polyolefin composition of the present invention is 20 to 80 parts by weight of the polyolefin resin to 80 to 20 parts by weight of the polyolefin resin modifier.

When the amount of the polyolefin-based resin modifier exceeds 80 parts by weight, it causes an increase in cost, adversely affects the moldability and mechanical properties, and the appearance is liable to be impaired. On the other hand, if the amount of the polyolefin resin modifier is less than 20 parts by weight, the adhesion of the coating film is adversely affected. The blending ratio of the polyolefin composition is more preferably 30 to 60 parts by weight of the polyolefin resin to 70 to 40 parts by weight of the polyolefin resin modifier.

The polyolefin-based composition of the present invention is usually prepared by extruding and melting and kneading the polyolefin-based resin modifier and the polyolefin-based resin having the above-mentioned composition using, for example, a twin-screw kneading extruder. .

When a molded body is produced by kneading with a mixing roll or the like and hot pressing, the pressure is insufficient.
It is not preferable because hydroxyl groups hardly appear on the surface of the molded body.

The molded article of the present invention is characterized in that a coating layer of the above-mentioned polyolefin composition is provided on the surface of a substrate by a blow molding method or an injection molding method.

That is, in the present invention, the polyolefin-based composition obtained by the above method is pelletized using a roll mill, a sheet cutter, or the like, and blow molding or injection molding is performed using the pellet to form a base material. A coating layer of a polyolefin composition is formed on the body surface.

The material constituting the base material is not particularly limited. For example, polyolefin resins such as polyethylene and polypropylene, ethylene / vinyl acetate copolymer (EVA), ethylene / methyl methacrylate copolymer (EMMA) And the like.

The blow ratio at the time of blow molding is determined depending on the shape, performance and application of the final product.
Is preferable, and the range of 1.2 to 3 is more preferable.
If the blow ratio is less than 1.05, the adhesion to the mold during blow molding becomes insufficient, and if the blow ratio exceeds 5, the thickness of the molded product becomes non-uniform and the characteristics of the molded product are not stable. The blow ratio refers to the expansion ratio of the parison. If the parison diameters before and after molding are D ₀ and D ₁ , respectively, D ₁
/ D ₀ .

Other conditions for performing blow molding include:
Normal molding conditions for blow molding a polyolefin-based resin can be employed.

When the coating layer is formed on the surface of the substrate by injection molding, for example, insert molding can be used. As the conditions for the injection molding, usually, the usual molding conditions for injection-molding a polyolefin-based resin can be adopted.

The polyolefin-based composition of the present invention is used as a composition for modifying the surface of a polyolefin-based resin. It is useful in a wide range of fields such as industrial materials. In addition, molded articles (members) in which a coating layer of the above-mentioned polyolefin composition is formed on the surface of a substrate are also used for vehicle parts such as automobiles, foodstuffs, packaging materials for medical use, electric parts such as miscellaneous goods and home appliances, various It is useful in a wide range of fields such as industrial materials.

[0056]

The present invention will be described in more detail with reference to the following Examples and Comparative Examples, but the present invention is not limited to these Examples.

Examples 1-2Manufacture of modifiers for polyolefin resins  With a stirrer, cooler, thermometer and nitrogen gas inlet
In a convertible flask, add the monomers in the proportions shown in Table 1 below.
(Polyolefin homopolymer having unsaturated double bond
), 105 parts by weight of toluene and ethyl acetate
With a polymerization solvent (105/45) consisting of 45 parts by weight of chill
The mixture was charged and mixed to prepare a monomer mixed solution. Each monomer
Table 1 below shows the compounding ratio of ー.

[0058]

[Table 1]

Next, the monomer mixed solution was bubbled with nitrogen gas for 20 minutes to remove dissolved oxygen, and then the inside of the separable flask was replaced with nitrogen gas and heated. When a reflux liquid (tap water: cooling liquid) is confirmed in the cooling pipe, 1,1-di (ter) is used as a polymerization initiator.
t-hexylperoxy) -3,3,5-trimethylcyclohexane (trade name: PerhexaTM, manufactured by NOF Corporation)
H) Boiling point polymerization was started by adding 0.01 parts by weight.

One hour after the start of the polymerization, 0.02 parts by weight of Perhexa TMH was added again. Also, 2 hours, 3 hours and 4 hours after the start of the polymerization,
(3,5,5-trimethylhexanoyl) peroxide (manufactured by NOF Corporation, trade name: Parloyl 355) 0.02
Parts by weight, 0.1 parts by weight, and 0.3 parts by weight were respectively charged. By conducting the boiling point polymerization for 7 hours, an acrylic copolymer solution containing a polyolefin resin modifier was obtained. The solid content of the obtained polymer was 40%. next,
The liquid containing the solid content was dried at 130 ° C. in a vacuum drier to remove the solvent, and then pulverized by a pulverizer to obtain a polyolefin resin modifier. In addition, as shown in Table 1, the product obtained in Example 1 is referred to as a modifier A, and the product obtained in Example 2 is referred to as a modifier B.

Examples 3 to 5Production of blow molding pellets by extrusion kneading  The modifiers A and B in the proportions shown in Table 2 and the PP resin were
Melting with a kneading extruder (trade name: PCM30, manufactured by Ikegai Kiko Co., Ltd.)
Knead and extrude from a 3 mm diameter strand die,
After cooling with water and pelletizing with a pelletizer,
-Obtain molding pellets (polyolefin composition)
Was. At this time, both the barrel temperature and the mold temperature were set at 220 ° C.
Specified.

[0062]Production of blow molded products  Next, a 50 mm single screw extrusion blow molding machine (Nippon Steel Works, Ltd.)
Manufactured and trade name: JEB-7) and melt-kneaded, as shown in FIG.
The parison P extruded from the die 1 is blown as shown in FIG.
Blow molding using the molding die 2 to obtain a blow molded product
Was. At this time, the extrusion temperature at the die 1 is 210 ° C.
The blow mold 2 was cooled to 25 ° C.

Examples 6 to 8Production of pellets for injection molding by extrusion kneading  In the same manner as in Examples 3 to 5, pellets for injection molding (poly
(Olefin-based composition). However, barrel temperature
The temperature and the mold temperature were both set to 200 ° C.

[0064]Production of injection molded products  The prepared pellets (polyolefin composition) are
Injection molding under the conditions of 1 mm thick and 100 m long
m, a flat plate having a width of 100 mm was prepared. Injection molding machine: Toshiba IS-30EPN (clamping pressure 30 to
n) Injection pressure: 50 kg / cm^Two NH temperature: 220 ° C Mold temperature: 35 ° C

Comparative Example 1 Injection molding pellets were prepared in the same manner as in Examples 6 to 8, except that the modifier A prepared in Example 1 was used and the mixing ratio with the PP resin was changed as shown in Table 2. (Polyolefin-based composition) was prepared, an injection molded product was prepared, and the adhesion of the coating film was evaluated in the same manner as in Examples 3 to 5.

Comparative Examples 2 to 5 Using the modifiers A and B prepared in Examples 1 and 2, the mixing ratio with the PP resin was changed as shown in Table 2,
After kneading with a mixing roll heated to 80 ° C. to prepare a sheet, it was pelletized with a pelletizer to prepare a kneaded pellet.

Next, using the kneaded pellets, a press machine heated to 200 ° C. was used to obtain a thickness of 1 mm, a length of 100 mm, and a width of 1 mm.
A 00 mm press sheet was prepared.

[0068]Evaluation method  The two-pack type polyurethane was added to the sample molded by the above method.
Rethane resin paint (Kansai Paint Co., 400 Deep Bu
Rack base (base resin) / urethane PG curing agent 600 = 1
0/1 parts by weight) is applied with a brush,
Dry and cure for 30 minutes, then tape cross cut test
Was performed, and the adhesion of the coating film was evaluated. And 6/3
○, 7/36 or more when only 6 or less peeled
What peeled was set to x. The results are shown in Table 2 below.

[0069]

[Table 2]

[0070]

According to the present invention, the polyolefin composition of the present invention is constituted as described above. By forming a coating layer on the surface of the polyolefin resin, the adhesion to the paint can be improved without primer treatment. can do.

The polyolefin resin modifier of the present invention can be suitably used as a raw material for preparing the above-mentioned polyolefin composition. Further, the molded article of the present invention has a coating layer formed on the surface of a base material by a blow molding method or an injection molding method, and has improved coating properties. Can be used for

[Brief description of the drawings]

FIG. 1A is a front view showing a parison extruded from a die in blow molding, and FIG. 1B is a plan view.

FIG. 2A is a conceptual diagram showing a mold, and FIG.
Is a longitudinal sectional view, and (c) is a transverse sectional view.

[Explanation of symbols]

 1 Die 2 Mold P Parison

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4F006 AA12 AA13 AA22 AB13 AB24 BA01 CA04 4J002 AA01W BB03X BB05X BB10X BB12X BB14X BB15X BB17X BB19X GN00 4J027 AA08 AB03 AB10 AC03 BA06 BA08 BA08 BA08 BA06

Claims (3)

[Claims] 1. A polyolefin homopolymer and / or copolymer having a terminal modified with a radically polymerizable unsaturated double bond (a), an alkyl (meth) acrylate (b), and a carboxyl group And a polymerizable monomer (c) having at least one functional group selected from the group consisting of a hydroxyl group, an amino group, an amide group, a cyano group, an epoxy group and an isocyanate group. For polyolefin resins. 2. The polyolefin resin modifier according to claim 1, wherein the polyolefin resin modifier is 80 to 20 parts by weight and the polyolefin resin is 20 to 20 parts by weight.
A polyolefin-based composition prepared by extruding and kneading 80 parts by weight. 3. A molded article characterized in that a coating layer of the polyolefin composition according to claim 2 is provided on the surface of a substrate by a blow molding method or an injection molding method.