JPH0150246B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a modified polyolefin, and more particularly, the present invention relates to a method for producing a graft modified product by melt-kneading a polyol ester of maleic anhydride with a polyolefin.

Modification methods for polyolefins include improving catalysts,
Modification in the olefin polymerization stage, such as improving the copolymer composition or copolymerization method, and various additives,
Modifications may be made to the polyolefin after polymerization, such as mixing fillers or other types of polymers, or graft polymerization with other types of monomers. In order to graft-polymerize the graft monomer used for graft polymerization onto a polyolefin, there are known methods in which a radical initiator is applied to the graft monomer in a solvent or other medium, or a method is used in which radiation is used, but none of these methods have been widely put into practical use. It has not yet been reached. On the other hand, various attempts have been reported to modify polyolefin using a graft monomer and a radical generator at a temperature equal to or higher than the melting point of the polyolefin without using a solvent or medium. These include, for example, the treatment of rubbery polyolefin modifications for the purpose of internal crosslinking, crosslinking of polyolefins, graft modification of polyolefins by addition of vinyl monomers, etc. One purpose of this graft modification is to improve the affinity of polyolefin with polar compounds, and for this purpose, maleic acid or acrylic acid is considered to be the most preferred monomer for grafting. However, all of these monomers, vinyl monomers, are volatile or sublimable. Therefore, when graft modification of polyolefin using these materials is attempted by the above-mentioned melting method, the volatile acids will volatilize and cause strong physiological irritation, which not only harms the working environment but also requires the use of processing equipment to prevent irritation. A ventilation system and a sealing device for handling are required, and the generation of volatile substances causes problems in the operation of the graft reaction device, which also impedes the maintenance and maintenance of the reaction device.

The present inventor has conducted extensive research in order to eliminate the environmental and maintenance disadvantages mentioned above when performing melt grafting as described above. As a result, even when improving the polarity of polyolefin, the above-mentioned disadvantages can be eliminated at once by using a polyol ester of maleic anhydride instead of the above-mentioned maleic acid, etc., and grafting by melt grafting. The present invention was completed knowing that the ratio was also good. The modified polyolefin obtained in this way can be used as an additive or base resin to improve compatibility by blending or laminating with other resins, and can also be used as a mixing aid or base resin when compounding various fillers. Ru.

As is clear from the above description, an object of the present invention is to provide a manufacturing method that does not cause any environmental or maintenance disadvantages during the graft modification reaction of polyolefins. Another object is to provide a method for efficiently producing a modified polyolefin graft having improved polarity. The present invention provides: (1) A method for producing a modified polyolefin graft, which comprises kneading and extruding a polyolefin, a polyol ester of maleic anhydride obtained by reacting maleic anhydride with a polyol, and a radical generator in a molten state.

(2) The method according to item (1) above, wherein the polyol ester of maleic anhydride is obtained by reacting maleic anhydride with an equivalent molar or more of polyol.

(3) React less than the equivalent mole of polyol with maleic anhydride, and then add an additional amount of primary polyol to the reaction product, such that the total amount with the initially used polyol is based on maleic anhydride. The method according to item (2) above, wherein the polyol is reacted in an amount equal to or more than the equivalent molar amount.

(4) The method according to the above item (1), wherein the powdered polyolefin, polyol ester of maleic anhydride, and radical generator are mixed and then fed to an extruder.

(5) The method of paragraph (4) for mixing a polyolefin stabilizer.

The polyolefin used in the present invention includes so-called olefin-based synthetic resins such as polyethylene, polypropylene, polybutene-1, and poly-4-methylpentene-1, as well as so-called amorphous polymers such as EPR, EPT, and polybutadiene. Also say.

The polyol ester of maleic anhydride used in the present invention is produced as follows. The polyol used may be a low-molecular organic compound that has two or more alcohol groups in one molecule and has no other functional groups, such as ethylene glycol that has two or more primary alcohol groups in one molecule. ,1,3-
Propanediol, 1,4-butanediol,
Examples include 1,5-pentadiol, 1,6-hexanediol, trimethylolethane, trimethylolpropane, pentaerythritol, and dipentaerythritol. Examples of compounds having both primary and secondary or tertiary alcohol groups in one molecule include glycerin, 1,2,6-hexanetriol, and sorbitol. And, of course, since primary alcohol groups react faster with maleic anhydride than secondary or tertiary alcohol groups, this property of the polyol is used in the present invention to reduce unreacted free maleic acid. use for.

The ratio of maleic anhydride to polyol is such that the amount of alcohol groups in the latter is equal to or greater than that of the former. Preferred quantitative ratios are for example 1.0 to 1.5 and most preferably 1.01 when the latter is a diol.
~1.2. Reaction temperature is not limited, but 50℃
to 200°C, preferably 90°C to 150°C, and the reaction time is
The time period is 10 minutes to 10 hours, preferably 30 minutes to 5 hours. Polyols of the same type or different types can be mixed and reacted in two or more stages, and the use of a known esterification catalyst and the segmental mixing method of polyols can quickly reduce free maleic anhydride in the reaction mixture. This is desirable because it allows The polyol ester of maleic anhydride (hereinafter referred to as "ester carboxylic acid") used in the present invention produced as described above is then mixed with a small amount of a radical generator for graft reaction with polyolefin, and then mixed with a predetermined amount of polyolefin. Mix with stabilizers for powders and polyolefins.

As the radical generator mentioned above, various known organic peroxides can be used. For example, dialkyl peroxide, dicumyl peroxide, αα' bis(t-butylperoxy)-paradiisopropylbenzene, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, etc. oxide, hydroperoxides such as t-butyl hydroperoxide, cumyl hydroperoxide, paramenthane hydroperoxide, benzoyl peroxide, lauroyl peroxide, t-butyl peracetate,
These are diacyl-based, ester-based and ketone-based peroxides such as t-butyl perbenzoate and cyclohexane peroxide.

The ratio of the radical generator to the ester carboxylic acid according to the present invention is 0.05 to 5% by weight, preferably 0.5 to 2%. In addition to the radical generator, a small amount of styrene up to a molar equivalent per maleic acid can also be used in combination. It is generally known that styrene is alternately copolymerized with maleic anhydride, but in the graft polymerization of ester carboxylic acid to polyolefin according to the present invention, the (maleic anhydride group and styrene in the ester carboxylic acid) It is assumed that styrene is copolymerized alternately, and the coexistence of styrene is expected to contribute to improving the grafting rate of the polyolefin graft-modified product according to the present invention and to improving the physical properties of the modified product. It reduces the viscosity of the ester carboxylic acid-radical generator mixture when mixed with the polyolefin powder, and facilitates uniform mixing with the polyolefin powder.

The polyolefin powder polyolefin stabilizer, ester carboxylic acid, and radical generator are preferably mixed uniformly at room temperature or higher, preferably from 100°C to 120°C, using a known blender such as a Henschel mixer (trade name) before melt-kneading. do.
Since ester carboxylic acids are not necessarily liquid at room temperature, they may be softened or heated and mixed as a liquid, or they may be cooled and pulverized before use. The mixing time is not limited, but is 10 minutes to 3 hours, preferably 30 minutes to 2 hours. The mixing ratio is 1 kg to 10 kg of polyolefin, preferably 1.5 kg to 5 kg, per 100 g of ester carboxylic acid.
kg, and the amount of polyolefin stabilizer is about 0 to 5 g depending on the type of polyolefin. The mixing order is not limited, but for example, first polyolefin 200
~500g and 100g ester carboxylic acid and 1-2g
After mixing the radical generator, 1 kg to 5 kg of polyolefin and 5 to 50 g of stabilizer are mixed. The raw material mixture mixed as described above is then kneaded and extruded in a molten state, during which time a graft reaction is carried out. A melt (kneading) extruder is preferably used for this kneading and extrusion. From the viewpoint of the graft reaction, there is room to consider using other kneading machines or using a solvent method, but in the present invention, a molding extruder or a twin-screw (multi-screw) kneading extruder is used. It is easier to implement than using other machines.

The conditions (temperature, residence time) for melt-kneading the raw material mixture according to the present invention described above are specifically determined by the performance of the melt extruder used, but they are such that the kneading is carried out smoothly and free from radical initiation. In order for the decomposition of the agent and graft polymerization to occur efficiently, the temperature of the melting part must be 20° higher than the melting point of the polyolefin used.
C. to 50.degree. C. or higher, and a residence time of 1 minute or more, preferably 3 to 10 minutes, is required.

Since the grafting reaction product is a special ester carboxylic acid, the above-mentioned melt-kneading of the present invention can be carried out in a shorter time than when graft polymerizing maleic anhydride or a mono- or diester of maleic anhydride onto a polyolefin by melt-kneading. It has the advantage of achieving high grafting efficiency (see Examples below).
That is, if even one of the many double bonds based on maleic anhydride in one molecule of the ester carboxylic acid is grafted onto the polyolefin, that molecule can no longer be extracted by a solvent.
Due to the large number of double bonds mentioned above, the raw material mixture according to the present invention also has the effect of increasing the grafting efficiency by repeating melt extrusion.

The present invention will be explained below with reference to Examples.

Example 1, Comparative Example 1 98 g (1.0 mol) of maleic anhydride and 46 g (0.343 mol) of trimethylolpropane were reacted with stirring at 130°C. After 3 hours the maleic anhydride was almost completely reacted. Then, 1.25 g of dicumyl peroxide was added to the reaction mixture and mixed to produce the ester carboxylic acid reaction product of the present invention to be used in the subsequent step. 60 g of the reaction product and 200 g of polypropylene powder were heated at 110°C in a high speed mixer.
After mixing at 130° C. for 30 minutes, 1.8 kg of polypropylene powder and 5 g of a mixed stabilizer (the stabilizer composition for polypropylene) were added and mixed at the same temperature for 3 minutes. In the above mixing step, an ester carboxylic acid reaction product obtained by reacting maleic anhydride and a polyol in advance was used, so there was no physiological irritation caused by maleic anhydride. On the other hand, the ester carboxylic acid reaction product obtained as described above had a high viscosity and required careful mixing. The resulting mixture was then fed into a 20 mm extruder, and the extruded strands were cut into pellets at a cylinder temperature of 180°C to 230°C and a die temperature of 180°C. The obtained pellets were cooled with dry ice acetone, and the cooled pellets were ground into fine powder using a high-speed grinder. Then, 20 g of the fine powder was placed in a Soxhlet extractor and extracted with acetone for 72 hours. The procedure was carried out in the same manner as in Example 1 except that the ester carboxylic acid reaction product was not mixed (mixing, kneading, cutting,
(pulverization and extraction) to prepare Control Example 1. The amount extracted by acetone extraction in Example 1 was corrected for the amount of the mixed stabilizer and other extracts based on the amount extracted in Control Example 1. As a result, the amount of ester carboxylic acid extracted with acetone in Example-1 was 0.160 g, and the ratio to the calculated amount was 27.5%. Therefore,
The proportion of non-extractable ester carboxylic acid grafted onto polypropylene was 72.5%. Separately, a sheet was obtained by hot pressing using the extractable material (graft polymerized polypropylene), and the infrared absorption of this sheet was measured. The amount of binding was 1.49%.

Comparative Examples 1 and 2 The same procedure as Example 1 was carried out except that dicumyl peroxide was not mixed. The amount of ester carboxylic acid determined by acetone extraction was 0.55 g per 20 g, the proportion of non-extractable ester carboxylic acid was 5.5%, and the amount of maleic acid in the press sheet determined by infrared absorption was 0.15% (Comparative Example 1). Further, the same procedure was carried out except that 98 g of maleic anhydride was used instead of the ester carboxylic acid reaction product (Comparative Example 2). in this case,
Not only did the working environment deteriorate due to the strong physiological stimulation caused by the sublimation of maleic anhydride during mixing in a high-speed mixer and pelletizing, but also the extruder vent was frequently clogged by maleic anhydride. In addition, in the sheet produced from the acetone extract after finely pulverizing the pellets, no trace of infrared absorption due to maleic acid was observed, and in the addition of maleic anhydride during kneading and pelletizing, the grafting reaction of maleic anhydride to polypropylene was not observed. Turns out it doesn't happen.
When a radical additive was added at the same time, the graft reaction proceeded, but the stimulation of maleic anhydride could not be avoided.

Example 2, Comparative Example 2 98 g (1.0 mol) of maleic anhydride and 36 g (0.264 mol) of pentalithritol were reacted at 130° C. for 5 hours with stirring. 1 g of 2,5-dimethyl-2,5-ditertiary-butylperoxyhexane was added to the reaction mixture, and after mixing, the mixture was cooled to room temperature to obtain the ester carboxylic acid reaction product for graft polymerization as a sticky solid. I made it. After mixing 60 g of the reaction product and 200 g of polypropylene powder in a high speed mixer at 110 DEG C. to 130 DEG C. for 30 minutes, 1.8 Kg of polypropylene powder and 5 g of a mixing stabilizer were added and mixed for 3 minutes at the same temperature. In the above mixing step, no irritating odor was felt compared to Comparative Example 2 in which maleic anhydride was used as the mixing material. The resulting mixture was then fed to a 20 mm extruder pelletizer and extrusion recycled at a cylinder temperature of 180°C to 200°C and a die temperature of 180°C, and the resulting strands were cut into pellets. The resulting pellets were cooled, pulverized, and extracted with acetone in the same manner as in Example 1. A control example 2 was prepared in the same manner as in Example 2 (mixing, kneading, cutting, pulverization and extraction) except that the ester carboxylic acid was not mixed. The amount of acetone extraction in Example 2 (executed three times, average value) was corrected for the amount of mixed stabilizer and other extracts based on the amount of extraction in Control Example 2. The acetone extraction method was carried out in the same manner as in Example 1. As a result of the above, the amount of extract 3
The average value was 0.186 g, and the ratio of the extract to the added ester carboxylic acid was 23.3%, and therefore the ratio of the remainder, ie, the ester carboxylic acid grafted onto polypropylene, was 76.7%.
Separately, a sheet was obtained by hot pressing using the extractable material (graft polymerized polypropylene), the infrared absorption of this sheet was measured, and maleic acid was determined from the intensity of the C=O group-based The amount of binding was 1.60%.

Example 3 98 g (1.0 mol) of maleic anhydride and 61 g (0.51 mol, 3% from the calculated amount) of 1,6-hexanediol
(excess) was reacted with stirring at 130°C. After 2 hours of reaction, 2,5-dimethyl-2,5 was added to the reaction mixture.
-di(tertiary-butylperoxy)hexane
1.25 g was added, mixed, and cooled to room temperature to form a solid reaction mixture (ester carboxylic acid reaction product of the present invention). 1.8 after mixing 60 g of the ester carboxylic acid reaction product with 200 g of propylene ethylene copolymer (MFR 6.0, containing 3.5% ethylene) powder in a high speed mixer at 110°C to 130°C for 15 minutes.
Kg of the same copolymer powder and 5 g of a polypropylene mix stabilizer were added and mixed for 5 minutes at the same temperature.
Even during the above mixing step and the subsequent step of charging the resulting mixture into an extruder, there was no physiological stimulation caused by maleic acid with respect to the mixture. The resulting mixture was then fed into a 20 mm extruder, and the extruded strands were cut into pellets at a cylinder temperature of 180 DEG C. to 230 DEG C., a die temperature of 180 DEG C., and an average residence time of 2 minutes. The obtained pellets were cooled, pulverized, and extracted with acetone in the same manner as in Example 1, and the average value of the extracted amount was calculated three times, and the amount of stabilizer added was subtracted from the extracted amount. The amount of extracted acid) was calculated. As a result, the amount of ester carboxylic acid extracted by acetone extraction in Example-1 was 0.281 g (extraction rate
(48.4%), but the grafting efficiency was 51.6%. On the other hand, the maleic acid content measured from the amount of carbonyl in the press sheet by infrared absorption (IR method) using the extraction residue (graft copolymer) was 0.90%.

Example 4 98 g (1.0 mol) of maleic anhydride and 46 g (0.343 mol) of trimethylolpropane in excess of the molar equivalent
were mixed, heated and melted at 110 to 130°C, and reacted with stirring. After reacting for 3 hours, the reaction mixture was cooled to 80°C, 56 g (0.60 mol) of styrene was added, and 0.5 g of 2,5-dimethyl-2,5-di(tertiary-butylperoxy)hexane was added to the resulting solution. and mix the ester carboxylic acid styrene mixture 80%
The grafting reaction in the next step and subsequent steps was carried out using g. That is, 80 g of the ester carboxylic acid styrene mixture, 2 Kg of polypropylene powder, and 5 g of the mixing stabilizer were mixed in a high-speed mixer at 110° C. for 10 minutes. The resulting mixture was then fed into a 20 mm extruder, and the extruded strands were cut into pellets at a cylinder temperature of 180 DEG C. to 230 DEG C., a die temperature of 180 DEG C., and an average residence time of 2 minutes. The above reaction,
There was no physiological stimulation due to maleic anhydride during the mixing and extrusion steps. The pellets obtained in the same manner as in Example 1 were then extracted with acetone. The grafting rate of the extracted material was 64%. On the other hand, the maleic acid content of the press sheet obtained in the same manner as in Example 1 was determined by infrared absorption to be 1.65%.

Example 5 98 g (1.0 mol) of maleic anhydride and 20 g (0.15 mol) of pentaerythritol were heated at 110°C to 130°C with stirring to mix and dissolve pentaerythritol. Further, 18 g (0.2 mol) of 1,4-butanediol was added to the mixed solution, mixed, reacted at 130 DEG C. for 3 hours, and then left to cool, the reaction mixture turned into a solid (ester carboxylic acid).

The solid substance was placed in carbon tetrachloride and cooled by adding dry ice. The cooled solid was then ground in a high speed pulverizer. The pulverized product was dried at 25°C for 12 hours under reduced pressure (5 mmHg) to obtain ester carboxylic acid fine powder to be used in the subsequent grafting reaction.
60g of the fine powder, 2Kg of polypropylene powder,
0.5 g of bis-(t-butylperoxy)isopropylbenzene and 5 g of blend stabilizer were mixed in a high speed mixer at 110° C. for 5 minutes. The resulting mixture was then fed into a 20mm extruder, and the cylinder temperature was 180°C.
~210°C The extruded strands were cut into pellets at a die temperature of 180°C. The efficiency of the grafting reaction determined from the extraction rate obtained by treating the pellets obtained in the same manner as in Example 1 was 62%.

Example 6 98 g (1.0 mol) of maleic anhydride and 20 g (0.084 mol, 0.5 molar equivalent) of dipentaerythritol were combined with 0.2 g of tin octylate as a reaction catalyst.
A heating dissolution reaction was carried out while stirring at ℃ for 2 hours. Then, 25 g of 1,4-butanediol was added to the reaction mixture.
(0.28 mol, 0.56 mol equivalent) was added, dissolved, and reacted at the same temperature for 3 hours. Thereafter, the mixture was cooled to room temperature and left to solidify as a whole. The solidified product is then treated with a high-speed pulverizer while being cooled in carbon tetrachloride dry ice, and the resulting fine powder is dried at room temperature under reduced pressure (5 mmHg) for 12 hours and used for the subsequent grafting reaction. A fine powder of ester carboxylic acid was obtained. Except for using 60 g of the above-mentioned fine powder, mixing in a high-speed mixer, producing pellets using a 20 mm extruder, cooling and pulverizing the pellets, extracting the pulverized product with acetone, and calculating the grafting rate were carried out in the same manner as in Example 5. I did it. As a result, the grafting rate was
It was 77%. Further, the maleic acid content of the press sheet obtained in the same manner as in Example 5 was found to be 1.55% by infrared absorption measurement.

Claims (1)

[Scope of Claims] 1. A method for producing a modified polyolefin graft, which comprises kneading and extruding a polyolefin, a polyol ester of maleic anhydride obtained by reacting maleic anhydride with a polyol, and a radical generator in a molten state. 2. The method according to claim 1, wherein the polyol ester of maleic anhydride is obtained by reacting maleic anhydride with polyol in an amount equal to or more than the equivalent molar amount. 3. React less than the equivalent mole of polyol with respect to maleic anhydride, and then add an additional amount of primary polyol to the reaction product, such that the total amount with the initially used polyol is equivalent to the equivalent mole with respect to maleic anhydride. The method according to claim 2, in which the amount of polyol is reacted. 4. The method according to claim 1, wherein the powdered polyolefin, polyol ester of maleic anhydride, and radical generator are mixed and then fed to an extruder. 5. The method according to claim 4, in which a stabilizer for polyolefin is mixed. 6 Polyol is ethylene glycol, 1,3
-propanediol, 1,4-butanediol,
1. The method of claim 1, wherein 1,5-pentanediol, 1,6-hexanediol or neopentyl glycol. 7. The method of claim 1, wherein the polyol is glycerin, 1,2,6-hexanetriol, trimethylolethane, trimethylolpropane, pentaerythritol, dipentaerythritol or sorbitol. 8 The radical initiator is dibutyl peroxide, dicumyl peroxide, αα′ bis(t-butylperoxy)-paraisopropylbenzene,
2,5-dimethyl-2,5-di(t-butylperoxy)hexane, t-butyl hydroperoxide, cumyl hydroperoxide, para-menthane hydroperoxide, benzoyl peroxide, lauroyl peroxide, t-
2. The method of claim 1, which is butyl peracetate, t-butyl perbenzoate or cyclohexane peroxide.