JP2002256023A - Method for producing acid-modified polypropylene resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing an acid-modified polypropylene resin in which the reduction of a molecular weight is low, a content of a grafted acid is high and the productivity is excellent. SOLUTION: In the production method, based on (A) of 100 pts.wt., (B) of 0.1-20 pts.wt. and (C) of 0.01-20 pts.wt. are formulated and mixed. (A): a polypropylene resin (B): an unsaturated carboxylic acid and/or its derivative (C): an organic peroxide having a decomposition temperature of 50-120 deg.C which gives a minute for a half-life.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing an acid-modified polypropylene resin. More specifically,
The present invention relates to a method for producing an acid-modified polypropylene resin having a small decrease in molecular weight, a large amount of acid graft, and excellent productivity.

[0002]

2. Description of the Related Art Polypropylene resin is relatively inexpensive,
Since it has good moldability, heat resistance, solvent resistance, mechanical properties, appearance, and the like, it is processed into various molded products and used in various fields. In order to take advantage of these features, attempts have been made to blend materials with different polymers, alloy them, combine them with various inorganic materials to form composite materials, or laminate them to metals to form materials with better features. Has been done.

[0003] However, a polypropylene resin having no polar group has problems in adhesiveness, paintability, printability, and the like, and has poor adhesiveness with inorganic materials and metals. In addition, since it has low compatibility with so-called engineering plastics such as heterogeneous polymers having a polar group, particularly polyester resins, polyamide resins, polyphenylene sulfide resins, and polyphenylene oxoxide resins, polymer alloys containing both have impact resistance and There has been a problem that the mechanical strength and the like are reduced and the molded product surface peels off.

In order to solve this problem, a method of modifying a polypropylene resin has been proposed. A method of treating the polypropylene with an electron beam, radiation, ozone, or the like, or a method of treating a polypropylene resin in the presence of a radical generator such as an organic peroxide. A method of graft-modifying a saturated carboxylic acid, a derivative thereof, and the like has been used.

[0005] Among them, a method generally used is a method in which a polypropylene resin is graft-modified with an unsaturated carboxylic acid or a derivative thereof in a molten state using a kneading extruder. This method requires the use of an organic peroxide or the like as an initiator at the time of grafting, or irradiation of ultraviolet rays or radiation, and a part of the polypropylene resin causes an oxidation reaction or decomposes. For this reason, if the amount of the initiator such as an organic peroxide is increased in order to improve the amount of grafting, the MFR will increase remarkably. Therefore, the amount of the initiator is naturally limited. There was a problem that there was a limit to the quantity improvement.

As a method for suppressing the molecular weight reduction of the acid-modified polypropylene resin obtained to solve this problem, a method of adding styrene (by Fumio Ide, Practical Polymer Alloy Design, P.51 Industrial Research Institute (1996)) A method of adding divinylbenzene (JP-A-7-173229) has been disclosed but has not been sufficient.

[0007]

Under these circumstances, the present invention provides a method for reducing the molecular weight, reducing the amount of acid graft,
Another object of the present invention is to provide a method for producing an acid-modified polypropylene resin having excellent productivity.

[0008]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that the above problems can be solved by using a specific organic peroxide, and have completed the present invention. . That is, the present invention provides the following (A)
The present invention relates to a method for producing an acid-modified polypropylene resin in which (B) 0.1 to 20 parts by weight and (C) 0.01 to 20 parts by weight are blended and kneaded with 100 parts by weight. (A): polypropylene resin (B): unsaturated carboxylic acid and / or derivative thereof (C): organic peroxide having a half-life of 1 minute and a decomposition temperature of 50 to 120 ° C.

[0009]

DETAILED DESCRIPTION OF THE INVENTION Component (A) of the present invention is a polypropylene resin. As the polypropylene resin, propylene homopolymer or ethylene-propylene random copolymer, propylene-α-olefin random copolymer,
A propylene block copolymer can be used. Further, these polymers may be blended. Specific examples of the aforementioned α-olefin include 1-butene, 2-methyl-
1-propene, 2-methyl-1-butene, 3-methyl-
1-butene, 1-hexene, 2-ethyl-1-butene,
2,3-dimethyl-1-butene, 2-methyl-1-pentene, 3-methyl-1-pentene, 4-methyl-1-pentene, 3,3-dimethyl-1-butene, 1-heptene, methyl- 1-hexene, dimethyl-1-pentene,
Ethyl-1-pentene, trimethyl-1-butene, methylethyl-1-butene, 1-octene, methyl-1-pentene, ethyl-1-hexene, dimethyl-1-hexene, propyl-1-heptene, methylethyl- Examples thereof include 1-heptene, trimethyl-1-pentene, propyl-1-pentene, diethyl-1-butene, 1-nonene, 1-decene, 1-undecene and 1-dodecene.

The component (B) of the present invention is an unsaturated carboxylic acid and / or a derivative thereof. As (B), a compound having at least one kind of unsaturated group (i) and at least one kind of polar group (ii) in the same molecule and / or its structure is changed by a dehydration reaction or the like in the production process, Is a compound that changes to a structure having both at least one unsaturated group (i) and at least one polar group (ii). The at least one unsaturated group (i) includes a carbon-carbon double bond or a carbon-carbon triple bond. Examples of the at least one kind of polar group (ii) include a carboxylic acid group, a group derived from a carboxylic acid, that is, various salts and esters substituted with a hydrogen atom or a hydroxyl group of a carboxyl group, acid amide, acid anhydride, imide, acid azide Functional groups such as oxazoline and nitrile, epoxy groups, amino groups, hydroxyl groups, and isocyanate groups. Examples of the compound having at least one unsaturated group (i) and at least one polar group (ii) in the same molecule include unsaturated carboxylic acids, unsaturated carboxylic acid derivatives, unsaturated epoxy compounds, unsaturated alcohols, and unsaturated alcohols. Amines and unsaturated isocyanates are used. In addition, a resin which is dehydrated in a step of grafting to a polypropylene resin to produce an unsaturated carboxylic acid is also used. Specifically, maleic acid, fumaric acid, itaconic acid, acrylic acid, methacrylic acid, maleic anhydride, itaconic anhydride, methyl acrylate, ethyl acrylate, butyl acrylate, glycidyl acrylate, methyl methacrylate,
Ethyl methacrylate, butyl methacrylate, glycidyl methacrylate, monoethyl maleate, diethyl maleate, monomethyl fumarate,
Examples include fumaric acid dimethyl ester, acrylamide, methacrylamide, maleic monoamide, maleic diamide, fumaric monoamide, maleimide, N-butylmaleimide, and sodium methacrylate. Examples of those which produce an unsaturated carboxylic acid by dehydration in the step of grafting to a polypropylene resin include citric acid and malic acid. Among these unsaturated carboxylic acids and derivatives (B) thereof, preferred are glycidyl esters of acrylic acid and methacrylic acid and maleic anhydride. The amount of the unsaturated carboxylic acid and / or derivative thereof to be added is 0.1 to 20 parts by weight, preferably 0.5 to 10 parts by weight, based on 100 parts by weight of the polypropylene resin (A). If the amount is too small, the amount of grafting to the polypropylene resin will decrease, and sufficient adhesive strength cannot be obtained. In addition, when the addition amount is excessive, the amount of the unreacted unsaturated carboxylic acid and / or its derivative (B) in the resin increases,
Sufficient adhesive strength cannot be obtained. In addition, when the unsaturated carboxylic acid and its derivative are used together as (B), the amount of (B) added is based on the total amount.

The component (C) of the present invention is an organic peroxide having a half-life of 1 minute and a decomposition temperature of 50 to 120 ° C., preferably an organic peroxide having a decomposition temperature of 70 to 110 ° C. Things. If the decomposition temperature is too low, the graft amount will not be improved, and if the decomposition temperature is too high, the decomposition of the resin will be accelerated. Further, it is preferable that these organic peroxides have a function of extracting protons from the polypropylene resin after being decomposed to generate radicals. Examples of organic peroxides having a half-life of 1 minute and a decomposition temperature of 50 to 120 ° C. include diacyl peroxide compounds and percarbonate compounds.
(Compound I having a structure represented by the following structural formula (1) in the molecular skeleton) and alkyl perester compound (compound (II) having a structure represented by the following structural formula (2)).

The compound I having the structure represented by the structural formula (1) includes di-3-methoxybutyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, bis (4-t-butylcyclohexyl) Examples include peroxydicarbonate, diisopropyl peroxydicarbonate, t-butyl peroxyisopropyl carbonate, dimyristyl peroxycarbonate and the like. Examples of the compound II having the structure represented by the structural formula (2) include 1,1,3,3-tetramethylbutyl neodecanoate, α-cumyl peroxy neodecanoate, t-butyl peroxy neodecanoate, and the like. Of these organic peroxides (C), preferred are percarbonate compounds
(Compound I having a structure represented by structural formula (1) in the molecular skeleton). This is because the percarbonate compound has a function of extracting protons from the polypropylene resin after decomposing to generate radicals.

The resin composition of the present invention may contain an electron-donating compound such as styrene or divinylbenzene as long as its purpose and effects are not significantly impaired. In addition, a known substance generally added to the polypropylene resin, for example, an antioxidant, a heat stabilizer, a neutralizing agent, and the like can be further added.

As the production method in the present invention, various known methods for mixing resins or a resin and a solid or liquid additive can be adopted. Preferable examples include a method in which all or some of the components are combined and separately mixed with a Henschel mixer, ribbon blender, blender or the like to form a uniform mixture, and then the mixture is kneaded. As the kneading means, conventionally known kneading means such as a Banbury mixer, a plast mill, a Brabender plastograph, a single-screw or twin-screw extruder can be widely used. Particularly preferred is
This is a method in which a polypropylene resin, an unsaturated carboxylic acid compound and / or a derivative thereof, and an organic peroxide, which have been sufficiently preliminarily mixed, are supplied from a supply port of the extruder and kneaded using a single-screw or twin-screw extruder. This is because the present method enables continuous production and improves productivity. The temperature of the kneading part of the kneader (for example, the cylinder temperature in the case of an extruder) is 100 to 300 ° C., preferably 160 to 300 ° C.
250 ° C. If the temperature is too low, the graft amount may not be improved, and if the temperature is too high, the resin may be decomposed. The kneading time is 0.1 to 30 minutes, particularly preferably 0.5 to 5 minutes. If the kneading time is too short, a sufficient graft amount may not be obtained,
If the kneading time is too long, the resin may be decomposed.

[0015]

EXAMPLES The present invention will be described below with reference to examples, but these are merely examples, and the present invention is not limited to these examples without departing from the present invention. [Preparation method of evaluation sample] In the production of evaluation samples in Examples and Comparative Examples, a twin screw extruder 2D manufactured by Toyo Seiki Co., Ltd. was used.
25-S (L / D = 25, cylinder diameter = 20 mm) was used. The cylinder temperature was set to 200 ° C., and the screw rotation speed was set to 70 rpm. The evaluation methods in Examples and Comparative Examples are shown below. (1) Based on MFR JIS K7210, at a temperature of 230 ° C. and a load of 2
Measured at 1.2N. (2) Amount of maleic acid grafted 1.0 g of a sample was dissolved in 100 ml of xylene. The sample solution was dropped into 1000 ml of methanol with stirring to reprecipitate and collect the sample. After vacuum-drying the collected sample (80 ° C., 8 hours), a film having a thickness of 100 μm was formed by hot pressing. The infrared absorption spectrum of this film was measured, and 1780
The amount of maleic acid grafted was determined from the absorption around cm ^-1 .

Example 1 100 parts by weight of a polypropylene resin powder ([η] = 3.0, ethylene content 0.2% by weight), 1.0 part by weight of maleic anhydride, 1.0 part by weight of styrene, and dicetyl par Oxydicarbonate 0.05 parts by weight, calcium stearate 0.05 parts by weight, antioxidant tetrakis [methylene-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] methane 0.3 parts by weight Was added, and the mixture was sufficiently premixed. The mixture was supplied from a supply port of a twin-screw extruder and kneaded to obtain a sample. Table 1 shows the conditions and evaluation results.

Example 2 Evaluation was performed in the same manner as in Example 1 except that the amounts of the organic peroxide, maleic anhydride and styrene were changed as shown in Table 1.

Comparative Example 1 Evaluation was made in the same manner as in Example 1 except that no organic peroxide was added. This sample was used as a reference when no organic peroxide was added.

Comparative Example 2 The type of organic peroxide was changed to 1,3-bis (t-butylperoxyisopropyl) benzene, and the amounts of organic peroxide, maleic anhydride, and styrene were as shown in Table 1. The evaluation was carried out in the same manner as in Example 1 except for changing to.

Comparative Example 3 A sample was produced in the same manner as in Example 1 except that the amounts of the organic peroxide, maleic anhydride and styrene were changed as shown in Table 1. However, the strand was not stably drawn due to a remarkable increase in MFR, and no sample was obtained.

[0021]

[Table 1] * 1 Organic peroxide C-1: dicetyl peroxydicarbonate (temperature at which half-life is 1 minute = 99 ° C.) C-2: 1,3-bis (t-butylperoxyisopropyl) benzene (half-life is 1 minute temperature = 183
℃)

[0022]

As described above, according to the present invention, it is possible to provide a method for producing an acid-modified polypropylene resin which has a small decrease in molecular weight, a large amount of acid graft, and excellent productivity.

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Claims (3)

[Claims] (1) For 100 parts by weight of the following (A),
A method for producing an acid-modified polypropylene resin in which (B) 0.1 to 20 parts by weight and (C) 0.01 to 20 parts by weight are blended and kneaded. (A): polypropylene resin (B): unsaturated carboxylic acid and / or derivative thereof (C): organic peroxide having a half-life of 1 minute and a decomposition temperature of 50 to 120 ° C. 2. The method according to claim 1, wherein (C) has a structure represented by the following structural formula (1) in the molecular skeleton. 3. The method according to claim 1, wherein the kneading is performed using an extruder.
Production method as described.