JPH0543631A - Modified propylene polymer composition, and film, sheet and molding material prepared therefrom - Google Patents

Abstract

PURPOSE:To provide the title compsn. which is excellent in printability, clarity, etc., and useful esp. as a food-packaging container. CONSTITUTION:A molten propylene polymer, a silylated vinyl monomer, and an arom. vinyl monomer are melt mixed and copolymerized to give the title compsn., which is molded into a film or sheet, a container, a packaging material, etc.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a modified propylene polymer composition excellent in printability, transparency and appearance, a film or sheet and a molding material using the same, particularly as a food packaging material, a container and the like. The present invention relates to a modified propylene polymer composition having excellent transparency, a film or sheet using the same, and a molding material.

[0002]

2. Description of the Related Art Polypropylene is used in a wide range of applications such as films, fibers and molded products by various molding methods because it is low in cost, excellent in mechanical strength, heat resistance, oil resistance and has excellent appearance such as transparency. There is. However, polypropylene does not have polar groups or reactive active groups in the molecular structure and is poorly corrosive to solvents, so it is a resin that has many problems in secondary processing such as printability, adhesiveness, and paintability. Is. Therefore, the affinity of the surface of the polypropylene molded product for ink etc. can be improved by applying various surface treatments to the surface of the polypropylene molded product in order to perform secondary processing such as printing, or by adding other polymer substances. Attempts have been made to improve it.

A typical surface treatment method is, for example, corona discharge treatment (for example, Japanese Patent Laid-Open No. 53-71182), and the surface activity of the obtained sheet is insufficient.
There is a drawback that the ink used is also limited. In addition, the technique of using a primer for primer is expensive,
There are drawbacks such as additional processes, cost increase, production management,
There is a problem in quality control. Examples of the method of adding another polymer substance to the propylene-based resin include a method of mixing and adding solvent-corrosive polystyrene and the like (for example, Japanese Patent Publication No. 1-24409), a carboxylic acid-modified polyolefin or ethylene-vinyl acetate. A method of adding a resin containing a polar group such as a saponified copolymer (for example, JP-A-63-337) and a method of adding an inorganic substance to polypropylene to improve printability (for example, JP-A-63-63). Four
No. 3938), and a method of introducing a carboxylic acid group into polypropylene to modify the polypropylene resin itself (Japanese Patent Publication No. 51-10264), and subjecting polypropylene, a styrene monomer, a radical initiator and a crosslinking agent to a melt-kneading reaction. Attempts have been made to improve the printability by a modification method (Japanese Patent Laid-Open No. 61-98714).

[0004]

However, in the method of improving the printability of polypropylene by blending polystyrene having solvent corrosiveness, polypropylene and styrene are incompatible with each other and the dispersion is insufficient by the above method. In addition to the transparency required for food packaging material applications, the resulting molded products have unsatisfactory mechanical properties such as rigidity and impact resistance, which poses a problem in practical use. Further, there is a limit to improving printability by introducing only a carboxylic acid group into polypropylene. In the method of adding a polar group-containing resin to a propylene-based resin, if the number of polar groups is increased, the compatibility with the propylene-based resin, which is a non-polar polymer, decreases and the physical properties of the molded product deteriorate. In particular, when the transparency is lowered and becomes opaque, it cannot be used for food containers and stationery items which require transparency. Further, the molded product may be delaminated. Therefore, since the amount of the polar group introduced has an upper limit such as a range in which the physical properties are not deteriorated, the effect of improving the printability is limited and the requirement cannot be satisfied. Further, the method of adding an inorganic substance has a drawback that it cannot be used in applications requiring transparency. In addition, polypropylene, styrene monomer,
What was melt-kneaded with a radical initiator and a crosslinking agent,
It is inferior in transparency and haze value.

As described above, none of the conventional methods has satisfactory printability and transparency in terms of polymer performance. Therefore, if a composition with excellent printability, adhesiveness, and transparency can be obtained without losing the properties of polypropylene such as transparency, mechanical strength, heat resistance, and oil resistance, the conventional complicated process can be simplified. It can be expected that efficiency can be greatly improved.

The inventors of the present invention have conducted extensive studies to solve the above-mentioned drawbacks of the conventional method, and as a result, in the presence of a propylene polymer in a molten state in an extruder, silyl group-containing vinyl monomer and reactivity were obtained. It was found that a polypropylene polymer composition having excellent printability and transparency can be obtained by melt-kneading and polymerizing a vinyl monomer, preferably an aromatic vinyl monomer, and completed the present invention. .

[0007]

Means for Solving the Problems That is, the present invention is a modified propylene-based polymer composition obtained by subjecting a propylene-based polymer in a molten state to a melt-kneading polymerization reaction of a silyl group-containing vinyl monomer, preferably The silyl group-containing vinyl monomer used in the melt-kneading polymerization reaction is -Si-O.
-C- having a functional group, preferably a silyl group-containing vinyl monomer and a reactive vinyl monomer,
Preferably, the reactive vinyl monomer is an aromatic vinyl monomer, and a modified propylene-based polymer composition having excellent printability and transparency, which is obtained by mixing and reacting in a melt-kneading reaction in the presence of a radical initiator. , Film or sheet,
And a molding material.

The present invention will be described in detail.

(Constitution) The propylene-based polymer of the present invention is
A propylene homopolymer and a copolymer containing propylene as a main component and another olefin or an ethylenic vinyl monomer (each of which is a copolymer containing propylene at 75% by weight or more), and specifically, isotactic polypropylene, Examples include propylene-ethylene copolymer, propylene-butene copolymer, and maleic anhydride-modified polypropylene. These propylene-based polymers can also be mixed and used. Further, other polymers may be used within the range that does not impair the properties of the propylene-based polymer.

Examples of the silyl group-containing vinyl monomer having a --Si--O--C-- structure include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltributoxysilane, 3-methacryloxypropyltrimethoxysilane, and the like. Vinyltris (2-methoxyethoxy) silane, 3-methacryloxypropylmethyldimethoxysilane, trimethylsilylvinylbicyclo [2,2,1] heptane, N, N-bis [(methyldimethoxysilyl) propyl] methacrylamide, N, N- Bis [3- (trimethoxysilyl) propyl] methacrylamide, and the like,
Used alone or as a mixture. The present invention includes a compound having a -Si-O-H group generated by hydrolysis of the above-mentioned monomer. In the present invention, such compounds may be used alone or as a mixture.

Further, as a reactive vinyl monomer copolymerizable with a silyl group-containing vinyl monomer, a vinyl ester monomer; for example, vinyl acetate or the like, a (meth) acrylic monomer; for example, acrylic acid. , Methacrylic acid, maleic acid and alkyl esters thereof, vinyl cyanide monomers, such as acrylonitrile, amide-containing vinyl monomers, such as N-methylolamide, amino group-containing vinyl monomers, such as dimethylaminomethacrylate As the aromatic vinyl monomer, for example, styrene, methylstyrene, vinyltoluene, vinylxylene, ethylvinylbenzene, isopropylstyrene, chlorostyrene, dichlorostyrene, bromostyrene and the like can be used, and these can be used alone or in combination. To be It is preferable to use an aromatic vinyl monomer. Moreover, you may use together other reactive vinyl monomers other than these.

The silyl group-containing vinyl monomer is added in an amount of 20% by weight or less of the propylene polymer, preferably 0.1.
10 to 10% by weight. If it exceeds 20% by weight, reticulation of the product may occur, which is not preferable. The amount of the reactive vinyl monomer added is 50% by weight or less, preferably 5 to 35% by weight, based on the propylene polymer. If it exceeds 50% by weight, the performance of polypropylene is impaired, which is not preferable.

As a radical initiator, the decomposition temperature for obtaining a half-life of 1 minute is 13 because the reaction is carried out at the melt-kneading temperature of the propylene polymer because of the characteristics of the present invention.
It is desirable that the organic peroxide has a temperature of 0 to 250 ° C. Specific examples include t-butyl peroctate, bis (t-butyl peroxy) trimethylcyclohexane, cyclohexanone peroxide, benzoyl peroxide, dicumyl peroxide, t-butyl perbenzoate, dimethyl di (t-butyl peroxide). Oxy)
Hexane, dimethyldi (t-butylperoxy) hexine and the like can be mentioned.

The amount of the radical initiator used is usually 0.1 to 10 parts by weight based on 100 parts by weight of the reactive vinyl monomer,
It is preferably 1 to 5 parts by weight.

As the other additive, a stabilizer is necessary because the polypropylene polymer is a polymer having radical disintegration unlike polyethylene. However, it is necessary to consider the kind and the addition amount so as not to hinder the polymerization of the reactive vinyl monomer.

Examples of the stabilizer include pentaerythrityl-tetrakis ((di-t-butyl-hydroxyphenyl) propionate) and ocdecyl (di-t-butyl-).
Hydroxyphenyl) propionate, thiobis (methyl t-butylphenol), hindered phenolic stabilizers such as trimethyl-tris (di-t-butylhydroxybenzyl) benzene, tetrakis (di-t-butylphenyl) biphenylene phosphite, tris (di-t-diphenyl) t-
Phosphorus stabilizers such as butyl phenyl) phosphite, metal soaps such as zinc stearate and calcium stearate,
There are antacid adsorbents such as magnesium oxide and hydrotalcite. The amount of the stabilizer used is the propylene-based polymer 10
It is generally 0.01 to 1 part by weight, preferably 0.05 to 0.5 part by weight, based on 0 part by weight.

To produce the composition of the present invention by melt-kneading polymerization reaction, for example, a propylene-based polymer, a silyl group-containing vinyl monomer and a reactive vinyl monomer, preferably an aromatic vinyl monomer are used. A closed container such as a Banbury mixer or a continuous kneader such as an extruder is used. An extruder is preferable when considering industrial production such as granulation. Further, a twin-screw extruder is preferable because it is easy to control the supply of reactants, kneading, polymerization time, and the like.

As a manufacturing method, a propylene-based polymer in the form of powder or pellets is fed to an extruder and heated under pressure, preferably 1 to 20 atm, preferably 13
The propylene-based polymer is melted by heating at 0 to 250 ° C., the silyl group-containing vinyl monomer and the reactive vinyl monomer are melt-kneaded and polymerized, then the strand discharged from the die is cooled, and a pelletizer is used. And make pellets.

The vinyl monomer may be mixed with the propylene polymer powder or granules in advance and then fed to the extruder, or may be fed to the molten propylene polymer using a liquid feeder. Is also good. The radical initiator may be dissolved in the vinyl monomer in advance and then added, or may be added to the mixture of the propylene polymer and the vinyl monomer using a liquid feeder.

The stabilizer must be previously mixed with the propylene polymer by using a Henschel mixer or the like. Since the propylene-based polymer is a radical-disintegrating polymer unlike the ethylene-based polymer, the molecular weight is apt to decrease due to the cleavage of the main chain when it is simply melt-heated, but in the presence of a radical initiator and preferably a stabilizer, it is in a molten state. When the polypropylene is graft-reacted, it is possible to efficiently prevent the silyl group-containing vinyl monomer and the reactive vinyl monomer from being graft-polymerized on the propylene-based polymer while suppressing the decrease in the molecular weight.

The novel polymer composed of the propylene-based polymer of the present invention, the silyl group-containing vinyl monomer and the reactive vinyl monomer is itself a printing property, an adhesive property, a paintability,
Although it is a thermoplastic resin excellent in transparency, heat resistance, rigidity, moisture resistance, etc., since the polymer is further composed of a polar part and a non-polar part, it is also used as a compatibility improver with various polymers or with an inorganic filler. Are better.

The modified propylene-based resin composition or a mixture thereof thus obtained has a desired shape as a molding material, for example, molded articles such as containers, packaging materials, industrial parts, films, sheets and multilayer laminates. Etc. can be processed.
As the method, an ordinary processing method such as an extrusion molding method, an injection molding method, or a calendering method can be used. By such a method, a molding material such as a film, sheet or container having excellent printability and transparency, a packaging material, and a molded article can be obtained.

[0023]

EXAMPLES The present invention will now be described in detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. In the following, all parts and% are based on weight unless otherwise specified.

Example 1 A 20 mm single-screw extruder manufactured by Brabender (Germany) was set to a barrel temperature of 200 ° C. (however, a feeder section of 180 ° C.) and a die temperature of 210 ° C. Powdered polypropylene (Hipol B200P, manufactured by Mitsui Petrochemical Co., Ltd.) 930 parts, Irganox 1010 (stabilizer manufactured by Ciba-Gaiki) 0.5 parts, and phosphite 168.
0.5 part (stabilizer manufactured by Ciba-Gaiki) and 1 part calcium stearate (stabilizer) were mixed. 20 parts of 3-methacryloxypropyltrimethoxysilane, 50 parts of styrene and perhexin 25B (radical initiator manufactured by NOF CORPORATION)
A mixture of 2.1 parts was dry blended into the powdered polypropylene formulation above. The obtained dry blend was supplied to an extruder and melt-kneaded at 40 rpm to carry out a graft reaction.

The styrene content of the extruded reaction product, styrene content from the calibration curve using the ratio of the 700 cm ^-1 using infrared spectroscopy (attributable to styrene) and 1380 cm ^-1 (assigned to polypropylene) of the reaction product It was 4.8%. Further, in order to determine the presence or absence of grafting of the styrene portion of the product, the sample was immersed in tetrahydrofuran in which only polystyrene was dissolved at room temperature for 24 hours, and the residual ratio of the styrene portion was measured. As a result, the residual ratio was 86%.

The extrudate thus obtained was subjected to a hydraulic press 19
A 300 μm thick sheet was formed under the conditions of 0 ° C. and 150 atm. The obtained sheet was evaluated for printability and transparency by the test method described below.

Example 2 The same as Example 1 except that 20 parts of vinyltrimethoxysilane was used as the silyl group-containing vinyl monomer in Example 1 instead of 20 parts of 3-methacryloxypropyltrimethoxysilane. An extruded product was obtained under various conditions. The styrene content of the extruded product was determined by the same method as in Example 1 and was 4.7%. In the same manner as in Example 1, a sheet having a thickness of 300 μm was evaluated for printability and transparency.

Comparative Example 1 70 parts of polystyrene (Dick Styrene CR3500, a product of Dainippon Ink and Chemicals, Inc.) was added to 930 parts of the polypropylene compound containing the antioxidant in Example 1 and used in Example 1. An extruded product was obtained under the same conditions as above. The residual rate of the styrene portion was 7% as determined by the same method as in Example 1. In the same manner as in Example 1, a sheet having a thickness of 300 μm was evaluated for printability and transparency. The obtained sheet was cloudy, layered and non-homogeneous.

Comparative Example 2 50 parts of polystyrene (Dick Styrene CR3500, a product of Dainippon Ink and Chemicals, Inc.) and 930 parts of carboxylic acid-modified polypropylene were added to 930 parts of the polypropylene compound containing the antioxidant in Example 1. An extruded product was obtained under the same conditions as in Example 1 using 20 parts (Admer QF540, manufactured by Mitsui Petrochemical Co., Ltd.). In the same manner as in Example 1, a sheet having a thickness of 300 μm was evaluated for printability and transparency. The obtained sheet was cloudy, layered and non-homogeneous.

(Comparative Example 3) In Example 1, instead of using 20 parts of 3-methacryloxypropyltrimethoxysilane and 50 parts of styrene, 70 parts of styrene alone were used.
An extruded product was obtained under the same conditions as in Example 1. In the same manner as in Example 1, a sheet having a thickness of 300 μm was evaluated for printability and transparency.

(Comparative Example 4) 2800 parts of pure water and 35 parts of calcium phosphate as a suspending agent were added to a separable flask having an internal volume of 5 liters and equipped with a reflux device to prepare an aqueous medium, and powdered polypropylene (Hypol B200P, Mitsui Oil). 930 parts (produced by Kagaku) were suspended by stirring. Separately, perbutyl O (manufactured by NOF CORPORATION) as a radical polymerization initiator 2.
One part was dissolved in 70 parts styrene and this was added to the above suspension system. This aqueous suspension was heated to 80 ° C. under a nitrogen atmosphere and heated and stirred for 7 hours to complete the polymerization. The product was washed with diluted hydrochloric acid and the like and then dried. The same amount of stabilizer as in Example 1 was added to the obtained styrene-modified polypropylene and the mixture was extruded under the same conditions.

The residual ratio of the styrene portion was found to be 25% by the same method as in Example 1. In the same manner as in Example 1, a sheet having a thickness of 300 μm was evaluated for printability and transparency. The obtained sheet was cloudy, layered and non-homogeneous.

The transparency and printability evaluation methods of the sheets prepared in Examples and Comparative Examples are as follows. (1) Evaluation Method of Transparency For evaluation, the light transmittance and haze value of the 300 μm-thick sheet obtained by the method of Example 1 were measured by a haze meter (manufactured by Toyo Seiki Co., Ltd.). The appearance of the sheet was visually evaluated.

(2) Method of evaluating printability of sheet Oxidation polymerization type ink (Carton QS indigo, Dainippon Japan) was applied to the 300 μm thick sheet obtained in Example 1 by using RI tester (two-division roll, 0.15 cc roll). Ink chemical industry
The product of the company was developed and cured at room temperature to obtain a printability evaluation test sheet. The printability was evaluated by a cellotape peeling test. That is, after attaching a commercially available cellophane tape to the printability evaluation test sheet previously prepared and making it adhere,
Peeled off.

<Evaluation Criteria> -When the transfer of ink to the cellophane tape is less than 5%-
⊚: When less than 30%, it was evaluated as -O. When it was less than 50%, it was evaluated as -Δ.

[0036]

[Table 1]

[0037]

The present invention provides a printability obtained by subjecting a propylene-based polymer in a molten state to a melt-kneading polymerization reaction of a silyl group-containing vinyl monomer and a reactive vinyl monomer,
The present invention provides a modified propylene-based resin composition, a sheet, a film, and a molding material which are excellent in transparency and the like. In particular, it is useful as a molding material, a packaging material, and a container material that require transparency, printability, and the like, and is particularly useful in a field that requires transparency as a container and a packaging material such as a food packaging container. Further, even if an aromatic vinyl monomer having a problem of introduction is used, transparency is not impaired, and printability is improved by a combined effect of a silyl group-containing vinyl monomer and a reactive vinyl monomer. be able to.

Claims (6)

[Claims] 1. A modified propylene-based polymer composition obtained by melt-kneading and polymerizing a silyl group-containing vinyl monomer with a propylene-based polymer in a molten state. 2. The modified propylene polymer according to claim 1, wherein the silyl group-containing vinyl monomer used in the melt-kneading polymerization reaction has a structure of —Si—O—C—. Composition. 3. The modified propylene according to claim 1, which is obtained by subjecting a propylene-based polymer in a molten state to a melt-kneading polymerization reaction of a silyl group-containing vinyl monomer and a reactive vinyl monomer in the presence of a radical initiator. -Based polymer composition. 4. The modified propylene polymer composition according to claim 1, wherein the reactive vinyl monomer used in claim 3 is an aromatic vinyl monomer. 5. A film or sheet comprising the modified propylene polymer composition according to any one of claims 1 to 4. 6. A molding material comprising the modified propylene polymer composition according to any one of claims 1 to 4.