JPH0892335A - Production of modified polypropylene - Google Patents

Abstract

PURPOSE: To obtain a reactive polypropylene useful as a raw material for indus trial materials usable for interior and exterior automotive trim, household appli ance, electrical equipment, etc., capable of efficiently introducing an unsaturated carboxylic acid or its derivative to a low reactive polypropylene and not requir ing treatment for removing the unsaturated carboxylic acid after modification reaction. CONSTITUTION: 90-99.9wt.% of a polypropylene is mixed with 0.1-10wt.% of 1,2-polybutadiene in a molten state to give a reactive polypropylene on which the 1,2-polybutadiene is grafted. 100 pts.wt. of the reactive polypropylene is blended with 0.1-20 pts.wt. of an unsaturated carboxylic acid or its derivative and 0.01-2 pts.wt. of a radical initiator in a molten state to provide a method for producing a modified polypropylene.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing a modified polypropylene. More specifically, a method for producing a modified polypropylene in which an unsaturated carboxylic acid or a derivative thereof is efficiently grafted in order to impart reactivity such as printability, adhesiveness, hydrophilicity, or reactivity with other polymers or monomers. Regarding

[0002]

[Description of Related Art] Polypropylene resin is widely used in various applications because of its low specific gravity, excellent insulating properties, moldability, and excellent mechanical properties such as rigidity and heat resistance. Therefore, there is a problem that it is inferior in adhesiveness, paintability / printability, hydrophilicity, etc. Therefore, attempts have been made to improve reactivity by introducing various polar groups or groups having a double bond into polypropylene.

For example, maleic anhydride (abbreviated as MAH) or a derivative thereof is reacted with a polypropylene resin to introduce a polar group, and MAH-modified polypropylene is a binder of filler-reinforced polypropylene or a compatibilization of nylon / polypropylene polymer alloy. It is used as an agent. Generally, MAH-modified polypropylene is manufactured by adding MAH and a radical initiator to polypropylene and then melt-kneading the mixture.

However, since polypropylene has no functional group, it has poor reactivity and it is difficult to graft MAH in a sufficient amount. Therefore, a post-treatment for removing unreacted MAH from the polypropylene is required. On the other hand, MAH
If a large amount of a catalyst is used in order to improve the grafting efficiency of polypropylene, the molecular weight of polypropylene is lowered and the physical properties of polypropylene are lowered.

Japanese Unexamined Patent Publication (Kokai) No. 56-36508 discloses a method for producing polypropylene in which propylene and a branched 1,4-diene are copolymerized in the presence of a Ziegler-Natta catalyst to introduce a double bond. . Similarly, a method for producing a copolymer by copolymerizing a branched diene with propylene is disclosed in JP-A-62-1.
It is disclosed in 15007, 62-115008 and JP-A-2-145611. However, in these manufacturing methods,
There is a problem that a high pressure polymerization apparatus is required for the copolymerization. The content of the diene component in the copolymer is determined by the amount of the diene monomer charged during the copolymerization and cannot be changed during molding of the polymer.Therefore, a copolymer having a desired diene component content may be used depending on the purpose of use. It is necessary to synthesize each time.

In JP-A-6-172460, a diene monomer (1,9-decadiene, 1,4-hexadiene, vinylnorbornene, etc.) or a triene monomer (1,3,7-octatriene, 1,5,5) is added to polypropylene. It discloses a method for producing a reactive polypropylene in which a double bond is introduced by graft-polymerizing (9-decatriene etc.) in the presence of a radical generator. According to this method, it is possible to adjust the reactivity of the modified polypropylene by graft polymerization by changing the charged amount of the diene monomer at the time of pretreatment for molding without requiring a high pressure resistant reaction vessel. However, the amount of the diene monomer specifically disclosed is 10 parts with respect to 100 parts by weight of polypropylene.
~ 40 parts by weight (mainly 40 parts by weight)
Also, the efficiency of the graft reaction is poor. If the monomer concentration is increased in order to increase the reaction efficiency, polypropylene will gel and there will be problems such as difficulty in molding.

Japanese Unexamined Patent Publication No. 6-192489 discloses 100 parts by weight of polyolefin and 0.1 to 5 of 1,2-polybutadiene resin.
An olefin resin composition comprising 0 parts by weight and 0 to 400 parts by weight of an inorganic filler and having improved processability, impact resistance, rigidity and surface properties (surface gloss, hardness, paintability, etc.) is disclosed.
Specifically, as Example 3, a composition in which 20 parts by weight of 1,2-polybutadiene are mixed with 100 parts by weight of polypropylene is shown. However, the improvement of the surface property in this composition is due to the mere physical dispersion mixing of the 1,2-polybutadiene component in the polypropylene, and the grafting of the 1,2-polybutadiene to the polypropylene, and further, the dual property thereof. This is basically different from the present invention in which the bond is reacted with maleic anhydride or a derivative thereof to improve the reactivity of polypropylene.

In JP-A-55-50008, 0.5 to 20 parts by weight of solid rubber, 5 to 30 parts by weight of unsaturated carboxylic acid or its derivative, and 0.5 to 5 parts of a radical generator are added to 100 parts by weight of polypropylene resin. It is blended in a proportion of parts by weight and is melt-kneaded by adjusting the blending ratio of the unsaturated carboxylic acid or its derivative and the radical generator to 1 to 30, which is excellent in paintability, adhesiveness and dyeability. A method for producing modified polypropylene is disclosed. It is only described that the solid rubber contributes to increase the mechanical strength of the product while uniformly dispersing it in a chemically inert polypropylene resin to impart reactivity.

Examples of solid rubber include 1,2-polybutadiene, 1,4-polybutadiene, polyisoprene,
Styrene-butadiene copolymers, acrylonitrile copolymers, etc. are mentioned, but only styrene-butadiene rubbers show specific data. There is no description that the solid rubber is grafted to polypropylene, and there is no description that suggests it. The rate of addition of MAH is proportional to the amount of rubber compounded, and the unsaturated carboxylic acid reacts with the rubber component uniformly dispersed in polypropylene to physically mix polypropylene with the modified rubber uniformly dispersed therein. It is considered that polypropylene is modified due to the effect. Although depending on the amount of the solid rubber compounded, the addition rate of MAH was only about 50% of the charged amount, and a post-treatment by solvent extraction was performed to remove unreacted MAH from the polypropylene.

[0010]

An object of the present invention is to provide a modified polypropylene having excellent reactivity such as printability, adhesiveness and hydrophilicity by efficiently introducing an unsaturated carboxylic acid or its derivative into a non-polar polypropylene having low reactivity. It is to provide a method of manufacturing.

[0011]

Means for Solving the Problems The present inventors have prepared a method in which 1,2-polybutadiene, which is solid at room temperature, is preliminarily grafted to polypropylene, and then unsaturated carboxylic acid or its derivative is blended and melt-kneaded. A step of removing unreacted unsaturated carboxylic acid after the modification reaction by efficiently introducing carboxylic acid or its derivative into polypropylene and adjusting the amounts of 1,2-polybutadiene and unsaturated carboxylic acid or its derivative used. Is unnecessary, the amount of the radical initiator used during the modification reaction with 1,2-polybutadiene solid rubber and during the modification reaction with the unsaturated carboxylic acid or its derivative may be small, and the mechanical properties due to the decrease in the molecular weight of polypropylene are low. The present invention has been completed by confirming that the decrease of the above can be suppressed.

That is, according to the present invention, 1) 90 to 99.9% by weight of polypropylene and 0.1 to 10% by weight of 1,2-polybutadiene are melt-kneaded to give a reactive polypropylene grafted with 1,2-polybutadiene, A method for producing a modified polypropylene, which comprises blending 100 parts by weight of polypropylene with 0.1 to 20 parts by weight of an unsaturated carboxylic acid or a derivative thereof and 0.01 to 2 parts by weight of a radical initiator and melt-kneading the mixture. The following are preferred embodiments of the method for producing a modified polypropylene of the present invention. 2) The method for producing reactive polypropylene according to the above 1, wherein the radical initiator is added up to 1 part by weight with respect to 100 parts by weight in total of polypropylene and 1,2-polybutadiene and melt-kneaded. 3) The method for producing a modified polypropylene according to the above 1, wherein the unsaturated carboxylic acid is maleic anhydride. 4) The method for producing a modified polypropylene according to 1 above, wherein 1,2-polybutadiene having a ratio of 1,2 bonds of 70% or more is used. 5) The method for producing a modified polypropylene according to 1 above, wherein 10 to 500 parts by weight of an unsaturated carboxylic acid is used with respect to 100 parts by weight of 1,2-polybutadiene.

[0013]

[Manufacturing raw material]

1) Polypropylene In the present specification, polypropylene means not only a homopolymer of propylene but also a block copolymer of propylene and another α-olefin such as ethylene or butene-1,
It also includes random copolymers. The content of the other α-olefin is preferably 30% by weight or less, particularly preferably 10% by weight or less. Ethylene is particularly preferable as the other α-olefin, and the content thereof is preferably 10% by weight or less. Such polypropylene usually has a melt flow rate (MFR: 230 ° C., 2.16 kg load) of 0.1 to 1000 g / 10 minutes.

2) 1,2-Polybutadiene The 1,2-polybutadiene grafted onto polypropylene contains 1,2 bonds in an amount of 10 mol% or more, preferably 30 mol% or more, more preferably 70% or more. Such 1,2-polybutadiene can be appropriately selected and used from commercially available liquid rubber or solid rubber. However, from the viewpoint of workability at the time of melt kneading and graft reaction efficiency, 1,2-polybutadiene has 70 bonds. % Solid rubber at room temperature is suitable.

3) Unsaturated carboxylic acid or its derivative: Examples of the unsaturated carboxylic acid or its derivative are:
Acrylic acid, methacrylic acid, maleic acid, fumaric acid, tetrahydrophthalic acid, itaconic acid, citraconic acid, crotonic acid, isocrotonic acid, endo-bicyclo [2.2.
1] -5-heptene-2,3-dicarboxylic acid (Endic acid) or other unsaturated mono- or dicarboxylic acid or a derivative thereof, such as an acid anhydride, a halide, an amide, an imide or an ester. Specific examples of the derivative include maleic anhydride, itaconic anhydride, maleenyl chloride,
Maleimide, methyl acrylate, methyl methacrylate,
Examples thereof include citraconic anhydride, monomethyl maleate, dimethyl maleate and the like. Of these, unsaturated dicarboxylic acids or their anhydrides are preferable, and maleic acid and itaconic acid or their anhydrides are particularly preferable. These are usually used alone, but two or more kinds can be used in combination.

4) Other Components In the present invention, other compounding agents may be added within the range that does not impair the characteristics of the reactive polypropylene obtained. Specific examples of compounding agents include ultraviolet absorbers, neutralizing agents, lubricants, other resins, pigments, various fillers,
Examples include flame-retardant substances and antioxidants. These compounding agents can be used alone or in combination of two or more kinds.

5) Radical Initiator In the production method of the present invention, a radical initiator is used during the first stage modification with 1,2-polybutadiene and during the second stage modification with unsaturated dicarboxylic acid or its derivative. . As the radical initiator, those usually used, for example, benzoyl peroxide, lauroyl peroxide,
Di-t-butyl peroxide, acetyl peroxide, t-butyl peroxybenzoic acid, dicumyl peroxide, peroxybenzoic acid, peroxyacetic acid, t-peroxypivalate, 2,
Peroxides such as 5-dimethyl-2,5-di-t-butylperoxyhexine and diazo compounds such as azobisisobutyronitrile are used.

[0018]

[Production Method] The first graft reaction according to the production method of the present invention can be carried out by melt-kneading the above-mentioned polypropylene, 1,2-polybutadiene and a radical initiator. Melt kneading can be performed by various conventionally known methods. That is, a method of kneading using a batch type kneader such as a Banbury mixer, a Brabender, a kneading roll, or a method of kneading using a continuous kneader such as a single-screw extruder or a twin-screw extruder can be exemplified. .
The kneading temperature is 180 to 300 ° C., preferably 190 to 2
The range is 50 ° C., and the kneading time may be about 0.1 to 20 minutes.

The blending amount of each component in the first graft reaction is 99.9 to 90% by weight of polypropylene and 1,2-
Polybutadiene is 0.1 to 10% by weight, preferably polypropylene is 99.5 to 93% by weight and 1,2-polybutadiene is 0.5 to 7% by weight. If the content of 1,2-polybutadiene is less than 0.1% by weight, the improvement effect due to modification is not sufficient, and if the content of 1,2-polybutadiene exceeds 10% by weight, the resulting modified polypropylene gels, which is not preferable. This first graft reaction proceeds even if no radical initiator is added, but it is preferable to add about 1 part by weight of the radical initiator to 100 parts by weight of the above components and melt-knead. A blending amount exceeding 1 part by weight lowers the molecular weight of polypropylene and is not preferred.

The second modification reaction with the unsaturated carboxylic acid or its derivative is carried out by melt-kneading the 1,2-polybutadiene-grafted polypropylene produced above with an unsaturated carboxylic acid or its derivative and a radical initiator. Can be done by. The blending amount of the radical initiator is 0.01 to 2 parts by weight with respect to 100 parts by weight of 1,2-polybutadiene graft polypropylene. This second modification reaction is preferably carried out continuously in the reaction vessel subsequent to the first modification reaction of polypropylene with 1,2-polybutadiene. Melt kneading can be carried out in the same manner as the first reaction.

The blending amount of each component is 10 to 500 parts by weight, preferably 50 to 200 parts by weight of the unsaturated carboxylic acid or its derivative with respect to 100 parts by weight of 1,2-polybutadiene in 1,2-polybutadiene grafted polypropylene. The amount of the radical initiator is 1 to 80% by weight based on the unsaturated carboxylic acid or its derivative. If the unsaturated carboxylic acid or its derivative is less than 10 parts by weight, the effect of modification is insufficient, and if it exceeds 500 parts by weight, unreacted unsaturated carboxylic acid remains, which is not preferable. Further, if the content of the radical initiator exceeds 80% by weight, the molecular weight of polypropylene, which is the main component, decreases, which is not preferable.

[0022]

EXAMPLES The present invention will be described below with reference to examples and comparative examples, but the present invention is not limited to these examples. In each example, the following resin raw materials and additives were used.

(A) Homopolypropylene (PP): J2
09 (manufactured by Tonen Chemical Co., Ltd.), weight average molecular weight 300,000, number average molecular weight 60,000, MFR 9g / 10 minutes (230 ° C, 2.
16kg load). (B) 1,2-polybutadiene (1,2-PB): RB
-830 (Nippon Synthetic Rubber Co., Ltd.), 1, 2 bond 93
%. (C) Radical initiator (Pox): Perhexin 25B
(Manufactured by Nippon Oil & Fats Co., Ltd.). (D) Maleic anhydride (MAH): Wako Pure Chemical Industries, Ltd.
Made.

Production of Reactive Polypropylene Homopolypropylene (PP), 1,2-polybutadiene (1,2-PB) and radical initiator (Pox) were used in the proportions shown in Table 1, and Laboplast mill (Toyo Seiki ( Co., Ltd.) and melt kneading at 200 ° C. for 5 minutes to prepare PPDM
1, PPDM2 and PPDM3 were obtained. The graft ratio of 1,2-polybutadiene of each sample was evaluated from the cold xylene-soluble component, and the gel ratio was evaluated as the boiling xylene-insoluble component. The results are shown in Table 1. The cold xylene solubles and boiling xylene insolubles were measured by the following methods.

Method of measuring cold xylene solubles: About 4 g of modified polypropylene sample was precisely weighed, and boiling xylene of about 150 c was prepared.
After melting in c, let stand overnight to cool naturally,
A xylene-insoluble portion and a soluble portion were separated by a 200-mesh wire net and a Teflon filter paper, and dried. The weight of the soluble portion was measured, and the cold xylene soluble content was calculated by the following formula. Cold xylene solubles = (weight of xylene solubles / initial weight) × 100 (wt%)

Method for measuring boiling xylene insoluble matter: Modified polypropylene was press-molded to a thickness of 0.5 mm, about 4 g of this was precisely weighed, put in a 200-mesh wire net, and immersed in boiling xylene for 24 hours. The weight of the insoluble matter was measured, and the boiling xylene insoluble matter (gel fraction) was calculated by the following formula. Gel fraction = (weight of xylene-insoluble matter / initial weight) × 1
00 (wt%)

[0027]

[Table 1] PP 1,2-PB Pox Xylene solubles Gel fraction (wt%) (wt%) (phr) (wt%) (wt%) PPDM1 99 1 0 0.4 0 PPDM2 98 2 0.2 0 0 PPDM3 95 5 0.5 0 0

From Table 1, 1, 2 without adding Pox
-It can be seen that the polybutadiene is reacting (PPD
M1). In addition, 2 containing a radical initiator (Pox)
It can be seen that in the melt-kneading at 00 ° C. for 5 minutes, the entire amount of 1,2-polybutadiene is graft-reacted and gelation does not occur (PPDM2 and PPDM3).

Examples 1 to 6 and Comparative Example 1 Maleic anhydride (MA) was used in the proportions shown in Table 2 with respect to 100 parts by weight of PPDM1 to 3 and PP obtained above.
H) and the radical initiator (Pox) were melt-kneaded at 200 ° C. for 5 minutes with a Labo Plastomill (manufactured by Toyo Seiki Co., Ltd.) to obtain a sample. The melt flow rate (MFR: 190 ° C, 1050 g load) of the sample and M by the following method
The AH graft ratio was measured. The results are also shown in Table 2. Measurement of MAH grafting rate: A sample was formed into a film of 50 to 80 μm by hot pressing and the IR spectrum was measured by F
It was measured by T-IR (Perkin, manufactured by Elmer), and then unreacted MAH was removed from the film by using chloroform, and then IR spectrum was measured in the same manner. From the obtained IR chart, carbonyl of MAH ( C = O) The expansion / contraction peak of the bond (1780 cm ^-1 ) and the peak specific to isotactic polypropylene (840 cm ^-1 ) were calculated for the absorbance ratio, and treated with chloroform using the calibration curve prepared in advance. The MAH graft ratio before and the MAH graft ratio after the chloroform treatment were calculated.

[0030]

[Table 2] MAH Pox MAH Graft ratio (wt%) MFR (wt%) (phr) Before treatment After treatment (g / 10min) Example 1 PPDM1 1 0.2 0.98 0.85 59 〃 2 ↑ 2 ↑ 1.70 1.52 40 〃 3 PPDM2 1 ↑ 0.99 0.98 33 〃 4 ↑ 2 ↑ 1.98 1.68 41 〃 5 PPDM3 1 ↑ 1.00 0.96 23 〃 6 ↑ 2 ↑ 2.00 1.99 36 Comparative Example 1 PP 1 ↑ 0.54 0.28 26 〃 2 ↑ 2 ↑ 0.60 0.31 30

From Table 2, the amount of maleic anhydride used in the second-stage modification reaction was adjusted in consideration of the amount of 1,2-polybutadiene used in the production of the first-stage reactive polypropylene. It can be seen that almost all maleic anhydride reacts by the reaction. The value of the graft ratio before chloroform treatment was lower than that of the charged MAH (% by weight) because MAH sublimes during melt kneading and stays in the air and does not contribute to the reaction. is there. Although sublimated MAH has a strong irritating odor and deteriorates the work environment, the proportion of MAH sublimated and retained in the method of the present invention using 1,2-polybutadiene-grafted polypropylene is higher than that in the comparative example in which MAH is directly grafted to PP. Much less, and it can be seen that the method of the present invention is also preferable from the working environment.

[0032]

The present invention is characterized in that polypropylene and 1,2-polybutadiene are melt-kneaded to form reactive polypropylene, and then unsaturated carboxylic acid or its derivative and a radical initiator are blended and melt-kneaded. The present invention provides a method for producing a modified polypropylene. According to the present invention, an unsaturated carboxylic acid or a derivative thereof can be efficiently introduced into a non-polar, low-reactivity polypropylene, so that the step of removing the unsaturated carboxylic acid or a derivative thereof is not necessary after the modification reaction, and the adhesiveness, the coating property -A modified polypropylene having improved reactivity such as printability and hydrophilicity can be easily produced. The reactive polypropylene produced by the present invention is useful as a raw material for industrial materials used for interior and exterior parts of automobiles, home electric appliances, electric components, and the like.

Claims (1)

[Claims] 1. Polypropylene 90-99.9% by weight and 1,
After melt-kneading 0.1 to 10% by weight of 2-polybutadiene into a reactive polypropylene grafted with 1,2-polybutadiene, 0.1 to 20 parts by weight of an unsaturated carboxylic acid or its derivative and a radical are added to 100 parts by weight of the reactive polypropylene. A method for producing a modified polypropylene, which comprises mixing 0.01 to 2 parts by weight of an initiator and melt-kneading.