JP2000230083A - Polyolefin resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyolefin resin composition which exerts a high tension at melting and has an excellent thermoformability. SOLUTION: A polyolefin resin composition comprises, against 100 pts.wt. polyolefin resin (A), from 0.01 to 20 pts.wt. crosslinked polymer (B). Here, the crosslinked polymer (B) is obtained by polymerizing from 0.001 to 0.1 pts.wt. crosslinkable monomer having at least two polymerizable unsaturated groups within a molecule against 100 pts.wt. monomer mixture containing 50 wt.% or more alkyl (meth)acrylate having an 5-30C alkyl group.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyolefin resin composition having a high melt tension (hereinafter, referred to as melt tension) and having excellent thermoformability.

[0002]

2. Description of the Related Art Conventionally, high-molecular compounds such as plastics and elastomers, so-called resins, have excellent resin properties (flexibility, gloss, elasticity, brittleness, handleability, etc.) and resin properties (stability, durability, difficulty). It is used in various fields due to its flammability, vibration damping properties, heat retaining properties, etc.) and processability (release properties, kneading properties, etc.). However, for example, polyolefin has drawbacks in workability such as inferior vacuum moldability, blow moldability, foam moldability, extrusion moldability, calender moldability, etc. due to low melt tension. Therefore, attempts are generally made to blend polyethylene or the like with a polyolefin such as polypropylene or to increase the molecular weight of the polyolefin to increase the melt tension and improve the workability. Japanese Patent Application Laid-Open No. 8-302098 discloses a method of increasing the melt tension by blending a polyolefin (meth) acrylate having a high molecular weight with a polyolefin.

[0003]

However, the method of blending polyethylene with polyolefin has the disadvantage that a large amount of polyethylene is blended in order to improve processability, and the resulting rigidity of the polyolefin composition is reduced. There is. In addition, in the method of increasing the molecular weight of the polyolefin, there is a problem that the increase in the molecular weight lowers the melt fluidity, which is one index of workability, so that a favorable balance between melt tension and melt fluidity cannot be obtained. In the method of blending a high molecular weight polyalkyl (meth) acrylate with a polyolefin,
The effect obtained is still insufficient.

The present invention has been made in view of the above circumstances and provides a polyolefin resin composition having a high melt tension and excellent thermoformability.

[0005]

An object of the present invention is to provide a polyolefin resin composition comprising 0.01 to 20 parts by weight of a crosslinked polymer (B) per 100 parts by weight of a polyolefin resin (A). The crosslinked polymer (B) has at least two polymerizable molecules per molecule based on 100 parts by weight of a monomer mixture containing 50% by weight or more of an alkyl (meth) acrylate having an alkyl group having 5 to 30 carbon atoms. The problem is solved by a polyolefin resin composition obtained by polymerizing 0.001 to 0.1 parts by weight of a crosslinkable monomer having an unsaturated group.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The polyolefin resin (A) used in the present invention may be, for example, a homopolymer or copolymer of an olefin monomer obtained by radical polymerization, ionic polymerization or the like, a superior olefin monomer and a superior vinyl monomer. And a copolymer containing an olefin-based monomer and a diene-based monomer as a main component.
Used in combination of more than one species. Examples of the olefin-based monomer include ethylene, propylene, butene-1, hexene-1, decene-1, octene-1, and 4-methyl-pentene-1, and ethylene and propylene are particularly preferable. Specific examples of the olefin-based monomer homopolymer or copolymer include low-density polyethylene, ultra-low-density polyethylene, ultra-low-density polyethylene, linear low-density polyethylene, high-density polyethylene, ultra-high-molecular-weight polyethylene, polypropylene , Ethylene-propylene copolymer, polymethylpentene, polybutene and the like. These olefin polymers are used alone or in combination of two or more. In the present invention, among these, one selected from the group consisting of polyethylene, polypropylene and ethylene-propylene copolymer
The polyolefin resin (A) having a main component or a mixture of two or more types is particularly preferable.

The crosslinked polymer (B) used in the present invention comprises:
Alkyl (meth) having an alkyl group having 5 to 30 carbon atoms
It is obtained by copolymerizing a monomer mixture containing at least 50% by weight of acrylate and a crosslinkable monomer by radical polymerization or ionic polymerization. 5 to 3 carbon atoms
Specific examples of the alkyl (meth) acrylate having an alkyl group of 0 include cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, nonyl (meth) acrylate, lauryl (meth) acrylate, tridecyl (meth) acrylate, and stearyl. (Meth) acrylate, isobornyl (meth) acrylate and the like can be mentioned. These can be used alone or in combination of two or more.

The monomer mixture may contain a monomer copolymerizable with an alkyl (meth) acrylate having an alkyl group having 5 to 30 carbon atoms in an amount of 50% by weight or less. p-methylstyrene, o-methylstyrene, p-chlorostyrene, o-chlorostyrene, p-methoxystyrene, o-methoxystyrene,
Styrene-based monomers such as 2,4-dimethylstyrene and α-methylstyrene; alkyls having an alkyl group having 1 to 4 carbon atoms such as methyl (meth) acrylate, ethyl (meth) acrylate, and butyl (meth) acrylate ( Meta)
Acrylate monomers; vinyl cyanide monomers such as acrylonitrile and methacrylonitrile; vinyl ether monomers such as vinyl methyl ether and vinyl ethyl ether; vinyl carboxylate monomers such as vinyl acetate and vinyl butyrate Olefin monomers such as ethylene, propylene and isobutylene; and diene monomers such as butadiene, isoprene and dimethylbutadiene.
These monomers can be used alone or in combination of two or more. 5 to 5 carbon atoms in the monomer mixture
The ratio of the alkyl (meth) acrylate having 30 alkyl groups is 50% by weight to 100% by weight of the monomer mixture.
It is important that the above range be satisfied. It has 5 carbon atoms
(Meth) acrylate having 30 to 30 alkyl groups is 50
If the amount is less than the percentage by weight, high melt tension cannot be imparted to the obtained polyolefin resin composition.

The crosslinkable monomer used in the present invention has at least two polymerizable unsaturated groups in the molecule. Examples thereof include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, and triethylene glycol di (meth) acrylate. Ethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, hexanediol di (meth) acrylate, butanediol di (meth) acrylate, polyethylene glycol di (meth)
Acrylate, trimethylolpropane tri (meth) acrylate, tetramethyloltetra (meth) acrylate and the like can be mentioned, and these crosslinkable monomers can be used alone or in combination of two or more. The ratio of the monomer mixture to the crosslinkable monomer when producing the crosslinked polymer (B) is 0.001 to 0.1 parts by weight of the crosslinkable monomer with respect to 100 parts by weight of the monomer mixture. Range. If the crosslinkable monomer exceeds 0.1 parts by weight, the crosslinked density of the obtained crosslinked polymer (B) becomes too high, and the crosslinked polymer (B) having good compatibility with the polyolefin resin (A) is obtained. In such a case, the crosslinked polymer (B) may be unevenly dispersed in the polyolefin resin (A). If the amount of the crosslinkable monomer is less than 0.001 part by weight, the entanglement effect caused by crosslinking becomes insufficient. The polymerization method for producing the crosslinked polymer (B) is not particularly limited, and is usually produced by radical polymerization, ionic polymerization or the like, and is obtained as polymer particles through post-treatment.

The polyolefin resin composition of the present invention is obtained by dispersing 0.01 to 20 parts by weight of the crosslinked polymer (B) per 100 parts by weight of the polyolefin resin (A). When the amount of the crosslinked polymer (B) is less than 0.01 part by weight, the melt tension of the obtained polyolefin resin composition cannot be sufficiently improved. On the other hand, if it exceeds 20 parts by weight, a sheet or film obtained by processing the polyolefin resin composition may have irregularities on the surface and may have no gloss. The crosslinked polymer (B) is extruded and kneaded,
It is blended with the polyolefin resin (A) by melt-kneading by a known method such as roll kneading. When blending,
After mixing the crosslinked polymer (B) with a part of the polyolefin resin (A) to prepare a masterbatch, multistage mixing such as adding and mixing the remaining polyolefin resin (A) is also possible. In order to further improve the melt tension of the polyolefin resin composition, it is preferable that the crosslinked polymer (B) is dispersed as uniformly as possible in the polyolefin resin (A). For example, when mixing the polyolefin resin (A) and the crosslinked polymer (B), the mixture of the polyolefin resin (A) and the crosslinked polymer (B) is heated to such an extent that they do not decompose, and the crosslinked polymer (B) is heated. ) Can be distributed more evenly.

The polyolefin resin composition may contain a filler. By adding the filler, the rigidity and heat resistance of the polyolefin resin composition are improved, and the processability is improved, for example, the adhesion of the resin composition to the roll surface during calendering or the like is prevented. Further, since the amount of the resin composition adhered to the roll surface is reduced, cost reduction can be achieved. The compounding amount of the filler is preferably 0.1 to 400 parts by weight based on 100 parts by weight of the polyolefin resin composition. When the amount is less than 0.1 part by weight, the effect of improving the rigidity of the polyolefin resin composition is not sufficient.
If the amount exceeds 00 parts by weight, the surface of a film or the like obtained by processing may lose gloss and become uneven. Typical examples of fillers include calcium carbonate, talc, glass fiber, magnesium carbonate, mica, kaolin, calcium sulfate, barium sulfate, titanium white, white carbon, carbon black, ammonium hydroxide, magnesium hydroxide, and aluminum hydroxide. And preferably, calcium carbonate, talc and the like are used.

[0012] The polyolefin resin composition of the present invention includes:
Further, additives such as a stabilizer, a lubricant and a flame retardant can be added as required. These are commonly used and are not particularly limited. Examples of the stabilizer include pentaerythrityl-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] and triethylene glycol-bis [3- (3-t-butyl-
5-methyl-4-hydroxyphenyl) propionate]; phosphorus-based stabilizers such as tris (monononylphenyl) phosphite; tris (2,4-di-t-butylphenyl) phosphite; And sulfur-based stabilizers such as lauryl thiodipropionate. As the lubricant, sodium, calcium or magnesium salts of lauric acid, palmitic acid, oleic acid or stearic acid and the like are used.

Examples of the flame retardant include trimethyl phosphate, triethyl phosphate, tributyl phosphate, trioctyl phosphate, tributoxyethyl phosphate, triphenyl phosphate, tricresyl phosphate, cresyl phenyl phosphate, octyl diphenyl phosphate, diisopropyl phenyl phosphate, tris Phosphoric ester compounds such as (chloroethyl) phosphate, alkoxy-substituted bisphenol A bisphosphate, hydroquinone bisphosphate, resorcin bisphosphate, polyphosphate such as trioxybenzene triphosphate, tetrabromobisphenol A, decabromodiphenyl oxide, hexabromocyclododecane , Octabromodiphenyl ether, bistri Lomophenoxyethane, ethylenebistetrabromophytylimide, tribromophenol, various halogenated epoxy oligomers obtained by the reaction of halogenated bisphenol A with epihalohydrin, carbonate oligomers containing halogenated bisphenol A as constituents, halogenated polystyrene, Representative examples include halogen-containing compounds such as chlorinated polyolefins and polyvinyl chloride, metal hydroxides, metal oxides, and sulfamic acid compounds.

The method for processing the polyolefin resin composition is not particularly limited, and examples thereof include calendering, thermoforming, blow molding, foam molding, extrusion molding, injection molding, and melt spinning.

[0015] Such a polyolefin resin composition comprises:
Since it has a high melt tension, it has improved drawability during calendering, drawdown of molten resin during thermoforming or blow molding, and open cells of cells during foam molding. In addition, the processability such as blow molding and foam molding is improved. In particular, since the crosslinked polymer (B) has extremely good dispersibility in the polyolefin resin (A), the polyolefin resin composition containing the same has good extrudability into sheets, films, and the like. The surface of the obtained extruded product also has gloss without irregularities. Further, even if the amount of the crosslinked polymer (B) is small, the melt tension of the polyolefin resin (A) can be sufficiently improved, so that the physical properties of the polyolefin resin (A) are not impaired and the processability is excellent. Polyolefin resin composition. Useful molded articles obtained using such a polyolefin resin composition include sheets, films, thermoformed articles, hollow molded articles, foams, injection molded articles, fibers and the like.

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the present invention. In the examples, parts and% are by weight unless otherwise specified. In addition, various physical properties described in Examples, Reference Examples and Comparative Examples are measured by the following methods. 1. Various Physical Properties of Polymer Particle Dispersion (1) Solid Content: Determined by drying the particle dispersion at 170 ° C. for 30 minutes. (2) Particle size distribution, weight average particle size: A particle dispersion diluted with water was used as a sample liquid and subjected to dynamic light scattering (ELS800, manufactured by Otsuka Electronics Co., Ltd., temperature 25 ° C., scattering angle 90 °). It was measured. 2. Various physical properties of polyolefin resin composition (1) Melt tension: Pellets of polyolefin resin composition are extruded at a constant extrusion rate (10 mm / min descent rate) using a descending flow tester (Capillograph, manufactured by Toyo Seiki Co., Ltd.) to keep the strand constant. It was taken off at a speed (4 m / min) and the melt tension was measured. L / D of die is 10.0m
m / Φ2.0 mm, and the measurement temperature was 200 ° C. (2) Roll sheet appearance: The roll sheet appearance during roll kneading was visually determined using pellets of the polyolefin resin composition.

Reference Example 1 Production of Crosslinked Polymer (C-1) A mixture of 100 parts of stearyl methacrylate and 0.03 part of ethylene glycol dimethacrylate was mixed with 2.0 parts of polyoxyethylene alkylphenyl phosphate and distilled water. Add 200 parts of the mixture, and mix with a homomixer
After stirring at 0 rpm for 3 minutes, 30M was added to the homogenizer.
The mixture was passed twice at a pressure of Pa to obtain a stable preliminary dispersion. This was charged into a separable flask equipped with a stirring blade, a condenser, a thermocouple and a nitrogen inlet, 0.2 part of t-butyl hydroperoxide was added, and the internal temperature was raised to 60 ° C under a nitrogen stream. , 0.0005 part of iron (II) sulfate, 0.0015 part of disodium ethylenediaminetetraacetate, 0.2 part of Rongalit salt, and 10 parts of distilled water, and the mixture was stirred for 2 hours to undergo radical polymerization to disperse polymer particles. Liquid (hereinafter B
-1). The obtained copolymer B-1 was added to 600 parts of distilled water containing 5 parts of calcium acetate while stirring to precipitate the formed copolymer. Then, after separating the precipitated copolymer, each process of washing, dehydration and drying was performed to obtain a powdery crosslinked polymer (hereinafter referred to as C-1). B-1 has a solid content of 33.1%,
The particle distribution shows a single peak and the weight average particle size is 3
02 nm.

Reference Example 2 Production of Crosslinked Polymer (C-2) A polymer particle dispersion (hereinafter referred to as B-2) was prepared in the same manner as in Reference Example 1 except that 0.003 parts of ethylene glycol dimethacrylate was used. ), And treated in the same manner as in Reference Example 1 except that B-2 was used, to obtain a powdery crosslinked polymer (hereinafter, referred to as C-2). B-2 had a solid content of 33%, the particle distribution showed a single peak, and the weight average particle size was 299 nm.

Reference Example 3 Production of Crosslinked Polymer (C-3) A polymer particle dispersion (hereinafter referred to as B-3) was prepared in the same manner as in Reference Example 1, except that 0.09 parts of ethylene glycol dimethacrylate was used. ) Was obtained and treated in the same manner as in Reference Example 1 except that B-3 was used.
3). B-3 has a solid content concentration of 3
3.5%, the particle system distribution showed a single peak, and the weight average particle size was 276 nm.

Reference Example 4 Production of Crosslinked Polymer (C-4) The procedure of Reference Example 1 was repeated except that stearyl methacrylate was changed to 80 parts and ethylene glycol dimethacrylate was changed to 0.018 parts. The mixture was stirred for 2 hours to perform radical polymerization to obtain a polymer particle dispersion. Thereafter, 20 parts of methyl methacrylate and t-
A mixture consisting of 0.01 parts of butyl hydroperoxide was added dropwise over 30 minutes. After the completion of the dropping, the inside of the container was kept at the same temperature for another 90 minutes to terminate the reaction, thereby obtaining a polymer particle dispersion (hereinafter referred to as B-4). Except for using B-4, the same treatment as in Reference Example 1 was performed to obtain a powdery crosslinked polymer (hereinafter, referred to as C-4). B-4 has a solid content of 31.8%, and the particle distribution shows a single peak.
The weight average particle size was 262 nm.

Reference Example 5 Production of Crosslinked Polymer (C-5) Reference Example 4 was repeated except that 80 parts of lauryl methacrylate was used instead of stearyl methacrylate and 0.018 part of ethylene glycol dimethacrylate was used. Similarly, a polymer particle dispersion (hereinafter, referred to as B-5) was obtained, and treated in the same manner as in Reference Example 4 except that B-5 was used, and a powdery crosslinked polymer (hereinafter, referred to as C-5) ) Got. B-5 had a solids concentration of 33.6%, the particle distribution showed a single peak, and the weight average particle size was 262 nm.

Reference Example 6 Production of Crosslinked Polymer (C-6) A polymer particle dispersion (hereinafter referred to as B) was prepared in the same manner as in Reference Example 5, except that 0.1 part of t-butyl hydroperoxide was used. -6) and treated in the same manner as in Reference Example 5 except that B-6 was used, and a powdery crosslinked polymer (hereinafter referred to as C-6) was obtained.
). B-6 has a solid content of 33%.
%, The particle distribution showed a single peak, and the weight average particle size was 262 nm.

Example 1 As a polyolefin resin, a homopolypropylene pellet P-1 made of Nippon Polychem Co., Ltd. (melt flow rate: 5.0 g /
10 minutes) and the crosslinked polymer (C
-1) was hand-blended at the ratio shown in Table 1, and then twin-screw extruder (ZS manufactured by WERNER & PFLEIDERER)
Using K30), the mixture was melt-kneaded at a barrel temperature of 200 ° C. and a screw rotation speed of 200 rpm, and shaped into pellets. Table 1 shows the results of measuring various physical properties using the obtained pellets.

[Examples 2 to 8] Except that the kind of the crosslinked polymer to be mixed with the homopolypropylene pellet P-1 (melt flow rate 5.0 g / 10 min) and the addition ratio thereof were as shown in Table 1, A pellet was obtained in the same manner as in Example 1. Table 1 shows the results of measuring various physical properties using the obtained pellets.

Comparative Example 1 Homopolypropylene Pellets P-1 of Polyolefin Resin (Melt Flow Rate 5.
0 g / 10 min) and pellets were obtained and various physical properties were measured in the same manner as in Example 1 except that nothing was mixed. Table 1 shows the results.

Comparative Example 2 A polymer particle dispersion (hereinafter referred to as B-7) was obtained in the same manner as in Reference Example 1 except that ethylene glycol dimethacrylate was not used, and Example 7 was used except that B-7 was used. The same treatment as in Example 1 was performed to obtain a powdery non-crosslinked polymer (hereinafter, referred to as C-7). Pellets of the polyolefin resin composition were produced in the same manner as in Example 1 except that C-7 was used, and various physical properties were measured. Table 1 shows the results. B-7 has a solid content of 32.8.
%, The particle distribution showed a single peak, and the weight average particle size was 255 nm.

Comparative Example 3 A polymer particle dispersion (hereinafter referred to as B-8) was obtained in the same manner as in Reference Example 1 except that ethylene glycol dimethacrylate was changed to 1.0 part.
Except for using -8, the same procedure as in Example 1 was carried out to obtain a powdery crosslinked polymer (hereinafter referred to as C-8). Pellets of the polyolefin resin composition were produced in the same manner as in Example 1 except that C-8 was used, and various physical properties were measured.
Table 1 shows the results. B-8 has a solid content of 33.3%.
1%, the particle distribution showed a single peak, and the weight average particle size was 310 nm.

Comparative Example 4 A polymer particle dispersion (hereinafter referred to as B-9) was prepared in the same manner as in Reference Example 4 except that 80 parts of butyl methacrylate was used instead of stearyl methacrylate and 0.056 parts of ethylene glycol dimethacrylate was used. ), And treated in the same manner as in Example 1 except that B-9 was used, to obtain a powdery crosslinked polymer (hereinafter, referred to as C-9). Pellets of the polyolefin resin composition were produced in the same manner as in Example 1 except that C-9 was used, and various physical properties were measured. Table 1 shows the results. Also, B-9
Has a solids concentration of 33.5%, the particle distribution shows a single peak, and the weight average particle diameter is 103 nm.

[0029]

[Table 1]

As described above, according to the present embodiment, a polyolefin resin composition having a high melt tension and excellent thermoformability can be obtained, and the roll sheet at the time of roll kneading has a glossy appearance without irregularities on the surface. Had.

[0031]

As described above, the polyolefin resin composition of the present invention comprises:
High melt tension and excellent thermoformability. In particular, since the crosslinked polymer (B) has extremely good dispersibility in the polyolefin resin (A), the polyolefin resin composition containing the same has good extrudability into sheets, films, and the like. The surface of the obtained extruded product also has gloss without irregularities. Further, in the present invention, even if the addition amount of the crosslinked polymer (B) is small, the melt tension of the polyolefin resin (A) can be sufficiently improved, so that the physical properties of the polyolefin resin (A) are not impaired. And a polyolefin resin composition having excellent processability.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Koji Nishida, Inventor 20-1, Miyukicho, Otake City, Hiroshima Prefecture Mitsubishi Rayon Co., Ltd. Central Research Laboratory F-term (reference) 4J002 BB031 BB121 BB151 BB171 BG042 BG052 FD010 FD030 FD130 FD170

Claims (1)

[Claims] 1. A polyolefin resin composition containing 0.01 to 20 parts by weight of a crosslinked polymer (B) with respect to 100 parts by weight of a polyolefin resin (A), wherein the crosslinked polymer (B) is With respect to 100 parts by weight of a monomer mixture containing 50% by weight or more of an alkyl (meth) acrylate having an alkyl group having 5 to 30 carbon atoms, a crosslinkable monomer having at least two polymerizable unsaturated groups in the molecule is used. A polyolefin resin composition obtained by polymerizing 0.001 to 0.1 part by weight of a monomer.