JPS6148526B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a modified polypropylene composition that has good adhesion to polyolefins or polar substances such as nylon, polyester, glass, and metals. In general, polypropylene has mechanical properties, transparency,
It is used in a wide range of fields due to its excellent moldability and sanitary properties, but since it is non-polar, it has poor adhesion to polar substances, and various modifications have been carried out to improve this. For example, attempts have been made to blend polar substances or to perform a graft reaction with polar monomers, but this is not yet sufficient. Furthermore, as a method to improve adhesion, a method has been proposed in which a rubbery substance such as ethylene-propylene random copolymer rubber is mixed with modified polypropylene grafted with an unsaturated carboxylic acid or its derivative (Japanese Unexamined Patent Publication No. 1983-1992). −80334). However, although this method improves adhesion to some extent,
2 of the grafting process of polypropylene and the blending process of mixing a rubbery substance with modified polypropylene
It requires a process and is disadvantageous from an industrial standpoint.
As a method to overcome this process disadvantage, adhesion can be improved in one step by adopting the melt-kneading method, which is conventionally known as a method of grafting reaction, that is, a method in which the grafting reaction and blending step are performed simultaneously. It is expected that a composition will be obtained. The inventors conducted additional tests regarding this point. That is, when polypropylene, a rubbery substance, an unsaturated carboxylic acid or its derivative, and an organic peroxide were melt-kneaded, the resulting modified composition was surprisingly found to have poor adhesive properties (see Comparative Example below). ). Against this background, the present inventors have conducted various studies on a method for producing a modified polypropylene composition that uses a melt-kneading method and has good adhesive properties, and as a result, they have found that a propylene-ethylene block copolymer is used as the polypropylene component. It has been discovered that by using this together with ethylene-propylene random copolymer rubber in a specific ratio, the adhesion of a grafted modified polypropylene composition can be significantly improved, and thus the present invention has been provided. Ivy. The present invention comprises 90 to 60 parts by weight of propylene-ethylene block copolymer, 10 to 40 parts by weight of ethylene-α-olefin random copolymer rubber, 0.05 to 5.0 parts by weight of unsaturated carboxylic acid or its derivative, and organic peroxide. This is a method for producing a modified polypropylene composition, which comprises melt-kneading a mixture containing 0.01 to 1.0 parts by weight of a modified polypropylene composition. The most important feature of the present invention is that a propylene-ethylene block copolymer and an ethylene-α-olefin random copolymer rubber are used together. Conventionally, compositions consisting of propylene-ethylene block copolymer and ethylene-α-olefin random copolymer rubber have been known as impact-resistant compositions, but as in the present invention, adhesive properties can be improved by grafting reaction. There is no literature that discusses this point of view. A modified polypropylene composition obtained by grafting this composition with an unsaturated carboxylic acid or a derivative thereof has extremely excellent adhesive properties. On the other hand, modified polypropylene in which only propylene-ethylene block copolymer was grafted in advance in the same manner,
In the case of a modified polypropylene composition blended with an ethylene-α-olefin random copolymer, not only the adhesion is extremely low, but also the MFI increases significantly, causing adverse effects such as a decrease in impact strength and deterioration of moldability. There is also a drawback. In the present invention, it is not clear why the adhesion of the resulting modified polypropylene composition is significantly improved by the combined use of propylene-ethylene block copolymer rubber. The unsaturated carboxylic acid or its derivative preferentially grafts onto the ethylene block portion of the copolymer, and this portion selectively appears on the surface during solidification, and the adhesive effect of ethylene-α-olefin random copolymer rubber. It is presumed that this is due to the combined effects of these factors. The propylene-ethylene block copolymer used in the present invention is not particularly limited, but may have an MFI of 0.1.
~50g/10 min, preferably 0.5~30g/10
minutes, ethylene content 1 to 30 parts by weight, preferably 2
15 parts by weight. The method for producing the propylene-ethylene block copolymer is not particularly limited, and for example, propylene is polymerized in the presence of a catalyst containing titanium trichloride and an organoaluminum compound, and then the polymer containing the catalyst obtained in the first step is added. Under,
There are two-step polymerization methods in which ethylene alone or a mixed monomer of ethylene and propylene are block copolymerized. Furthermore, the ethylene-α-olefin random copolymer rubber used in the present invention is not particularly limited,
MFI0.1 to 100g/10min, preferably 0.5 to 30
g/10 min and an ethylene content of 30 to 95% by weight, preferably 50 to 90% by weight. As the ethylene-α-olefin random copolymer rubber, ethylene-propylene random copolymer, ethylene-butene-1 random copolymer, ethylene-pentene-1 random copolymer, ethylene-3
-Methyl-butene-1 random copolymer, ethylene-hexene-1 random copolymer, ethylene-
Examples include 4-methylpentene-1 random copolymer and ethylene-octadecene-1 random copolymer. The ethylene-α-olefin random copolymer may be used alone or in combination of different types. Among the above-mentioned ethylene-α-olefin random copolymers, it is preferable to use ethylene-butene-1 random copolymers, which have a remarkable effect of improving adhesion. The above-mentioned ethylene-α-olefin random copolymer rubber used in the present invention does not have a double polymer bond in its molecule. For example, ethylene-α-olefin interpolymers that have double bonds not only have poor adhesion improvement effects, but also have poor adhesion properties.
Gel occurs during molding of films, etc., making it impossible to obtain products with good appearance. In the present invention, the amount of the ethylene-α-olefin random copolymer rubber added is 90 to 60 parts by weight of the propylene-ethylene block copolymer.
10 to 40 parts by weight, preferably 15 to 30 parts by weight, preferably 85 to 70 parts by weight. If the amount added is less than 10 parts by weight, the effect of improving adhesion is small;
If the amount exceeds the weight part, not only will the adhesion deteriorate;
This is not preferred because mechanical strength decreases. Furthermore,
Examples of the unsaturated carboxylic acids used in the present invention include acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, and citraconic acid. Examples of unsaturated carboxylic acid derivatives include acid anhydrides, esters, and amides. , imides, metal salts, etc., such as maleic anhydride, citraconic anhydride,
Itaconic anhydride, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, glycidyl acrylate, glycidyl methacrylate,
Maleic acid monoethyl ester, maleic acid diethyl ester, fumaric acid monomethyl ester, fumaric acid dimethyl ester, itaconic acid monomethyl ester, itaconic acid diethyl ester, acrylamide, methacrylamide, maleic acid monoamide, maleic acid diamide, maleic acid N-mono Ethylamide, maleic acid-N,N-diethylamide, maleic acid-N-monobutylamide, maleic acid-N,N-dibutylamide, fumaric acid monoamide, fumaric acid diamide, fumaric acid-N-monoethylamide, fumaric acid -N,N-diethylamide, fumaric acid-N-monobutyramide, maleimide, N-butylmaleimide, N-phenylmaleimide, sodium acrylate, sodium methacrylate, potassium acrylate, potassium methacrylate, etc. . Among these, it is most preferable to use maleic anhydride. Unsaturated carboxylic acids or their derivatives are propylene-ethylene block copolymers and ethylene-α-
0.05 to 5.0 parts by weight, preferably 0.1 parts by weight per 10 parts by weight of the total amount of olefin random copolymer rubber
Add up to 1.0 parts by weight. If the amount added is less than 0.05 parts by weight, the adhesive strength will not be sufficient; if it exceeds 5.0 parts by weight, the adhesive strength will not only be saturated, but if unreacted monomers are not removed, the adhesive strength will decrease, and It may cause foaming during kneading, etc.
Combined with the cost aspect, this is disadvantageous. Furthermore, in the present invention, an organic peroxide is used to promote the grafting reaction between the propylene-ethylene block copolymer and ethylene-α-olefin random copolymer rubber and the unsaturated carboxylic acid or its derivative. . Examples of organic peroxides include benzoyl peroxide, lauroyl peroxide, azobisisobutyronitrile, dicumyl peroxide, α,α'-bis(t-butylperoxydiisopropyl)benzene, 2,5-dimethyl-2 ,5-di(t-butylperoxy)hexa,2,5-dimethyl-2,5
-di(t-butylperoxy)hexyne-3, di-t-butyl peroxide, cumene hydroperoxide, t-butyl hydroperoxide and the like. The amount of organic peroxide added is propylene-ethylene block copolymer and ethylene-α.
-0.01 to 1.0 parts by weight, preferably 0.02 parts by weight per 100 parts by weight of the total amount of olefin random copolymer rubber
The amount is 0.2 parts by weight. If the amount added is less than 0.01 part by weight, the grafting reaction amount of the unsaturated carboxylic acid or its derivative will be insufficient, resulting in poor adhesion.
If it exceeds 1 part by weight, the MFI of the composition becomes too large, which has the disadvantage of making it difficult to mold. In the present invention, the above-mentioned propylene-ethylene block copolymer (further mixed with homopolypropylene, propylene-ethylene random copolymer, etc. as necessary), ethylene-
The α-olefin random copolymer rubber, unsaturated carboxylic acid or its derivative, and organic peroxide are thoroughly mixed in a tumbler, Henschel mixer, etc., and the mixture is prepared at a temperature higher than the melting point of the propylene-ethylene block copolymer, generally higher than the melting point. The grafting reaction is carried out by melt-kneading at a temperature of ~280°C or less. The method for melt-kneading is not particularly limited, but it can be carried out using, for example, a screw extruder, a Banbury mixer, a mixing roll, or the like. The melt-kneading temperature and time vary depending on the decomposition temperature of the organic peroxide used, but generally it is between 160 and 280°C.
A temperature of 0.3 to 30 minutes, preferably 1 to 10 minutes at 170 to 250°C is suitable. Note that the melt-kneading may be performed in an inert gas stream. Further, when melt-kneading is performed using a screw extruder, unreacted monomers may be removed by venting. In addition, it is desirable to remove unreacted monomers from the obtained modified polypropylene composition by dissolving and reprecipitating, extracting, or the like from the viewpoint of improving adhesion, moldability, hygiene, and the like. The modified polypropylene composition obtained in the present invention contains heat-resistant stabilizers, weather-resistant stabilizers, lubricants, antistatic agents, fillers, pigments, dyes, flame retardants, anti-blocking agents, slitting agents, etc. to the extent normally used. May contain. The modified polypropylene composition obtained by the method of the present invention has good compatibility with unmodified polypropylene, such as homopolypropylene, propylene-ethylene random copolymer, propylene-ethylene block copolymer, etc., thereby reducing costs. , these materials may be mixed in an appropriate ratio for the purpose of improving rigidity, etc. The modified polypropylene composition obtained by the present invention not only has good adhesion to unmodified polypropylene, but also has good adhesion to polar substances such as metals, glass, nylon, polyester resins, and saponified ethylene-vinyl acetate copolymers. In addition to exhibiting excellent adhesion,
Shows good impact resistance, low temperature brittleness, etc. The present invention will be explained below with reference to Examples, but the present invention is not limited to these Examples. Note that the various physical properties in this specification were measured by the following methods.゜MFI ASTM DI238-52T at 230℃
Measured with a load of 2160g.゜Amount of maleic anhydride in the graft reaction A film with a thickness of approximately 0.1 mm was formed by heat pressing, extracted with acetone for 6 hours, and then vacuum dried at a temperature of 50°C for 24 hours.The infrared absorption spectrum was measured, and the infrared absorption spectrum was measured ^. The amount of graft-reacted maleic anhydride was determined from the absorption peak intensity of maleic anhydride in ¹ .゜Adhesive Strength For adhesion between saponified ethylene-vinyl acetate copolymer, nylon, and polypropylene terephthalate, both were coextruded, cooled and solidified, and then cut into 2 cm width pieces in the longitudinal direction, and the T-peel strength was measured. Adhesion to glass and aluminum was determined by cleaning the glass plate and aluminum plate with xylene, sandwiching the modified polypropylene composition between the two plates, melting at 250°C, pressing and solidifying the composition, and by hand. Then, the adhesive strength was roughly measured. Examples 1 to 5, Comparative Examples 1 to 5 The polypropylene component and ethylene-α-olefin random copolymer rubber component shown in Table 1, 0.5 part by weight of maleic anhydride, and 2,5 dimethyl-
2,5-di(t-butylperoxy)hexane
0.05 parts by weight, 0.1 parts by weight of butylated hydroxytoluene and 0.1 parts by weight of calcium stearate were mixed in a Henschel mixer for 5 minutes, L/D = 24
Melt-kneading pelletization was performed at 250°C using a 40mmφ extruder. Table 1 shows the MFI and grafted maleic anhydride of the resulting composition. Next, these modified polypropylene compositions were
At 200℃ from a 40mmφ extruder with D=20, saponified ethylene-vinyl acetate copolymer (MFI=19.5
g/10 minutes, ethylene content 45 mol%, saponification degree 99
%, hereinafter referred to as saponified EVA), L/D = 24 of 30
They were extruded from a mmφ extruder at 180° C. through a coextrusion T-die to produce coextruded sheets of the modified polypropylene composition with a thickness of 0.5 mm and the saponified EVA composition with a thickness of 0.2 mm. Table 1 shows the adhesive strength of these sheets.

【table】

[Table] Comparative Example 6 80 parts by weight of the composition of Comparative Example 1 and 20 parts by weight of ethylene-butene-1 random copolymer rubber were thoroughly mixed in a tumbler, and heated at 220°C using a 40 mmφ extruder with L/D = 24. Melt kneading was performed. The MFL of the resulting composition was 22.2 g/10 min, higher than that of Example 2 (17.5 g/10 min). The adhesive strength of the coextruded sheet with saponified EVA was 1300 g/2 cm, which is significantly lower than that of Example 2. Examples 6 to 10, Comparative Example 7 80 parts by weight of the propylene-ethylene block copolymer used in Examples 1 to 4, ethylene-butene-1
20 parts by weight of random copolymer rubber, maleic anhydride in the amount shown in Table 2, and 2,5-dimethyl-2,
0.05 parts by weight of 5-di(t-butylperoxy)hexane was mixed with a Henschel mixer for 5 minutes, and L/
Melt-kneading pelletization was carried out at 220° C. using a D=24 40 mmφ extruder. Table 2 shows the MFI and the amount of grafted maleic anhydride of the resulting composition. These compositions are coextruded with saponified EVA,
Adhesive strength was measured. The results are shown in Table 2.

【table】

[Table] Examples 11 to 16, Comparative Example 8 80 parts by weight of propylene-ethylene block copolymer used in Examples 1 to 4, ethylene-butene-1
20 parts by weight of random copolymer rubber, maleic anhydride
0.5 parts by weight and the organic peroxide shown in Table 3 were mixed in a Henschel mixer for 5 minutes, and L/D = 24.
Melt-kneading pelletization was performed at 220°C using a 40mmφ extruder. Table 3 shows the MFI and the amount of grafted maleic anhydride of the resulting composition. These compositions were coextruded with saponified EVA, and the adhesive strength was measured. The results are also listed in Table 3.

【table】

[Table] Example 17 L/D of the modified polypropylene composition of Example 2
= 20 from a 40 mmφ extruder at 190°C, and nylon 6 from a L/D = 24 30 mmφ extruder at 250°C through a coextrusion T-die, and the thickness of the composition was 0.5 mm, and the thickness of nylon 6 was extruded. When we made a 0.2mm coextruded sheet and measured the adhesive strength, it was 1000g/2cm.
It was hot. Comparative Examples 9-11 Example 17 for the compositions of Comparative Examples 3, 4 and 5
When similar experiments were conducted, the adhesive strength was 0 in all cases. Example 18 The composition of Example 2 was extruded from a 40 mmφ extruder with L/D=20 at 190° C., and the polypropylene terephthalate was extruded from a 30 mmφ extruder with L/D=24 at 270° C. through a coextrusion T-die. Composition thickness 0.5mm, polyethylene terephthalate thickness 0.2
A coextruded sheet with a diameter of 1.0 mm was prepared and the adhesive strength was measured to be 400 g/2 cm. Comparative Examples 12-14 Example 18 for the compositions of Comparative Examples 3, 4 and 5
When similar experiments were conducted, the adhesive strength was 0 in all cases. Example 19 When the composition of Example 2 was sandwiched between two xylene-cleaned glass plates and melted and pressed at 250°C, it could not be peeled off by hand. Comparative Examples 15-17 Examples for the compositions of Comparative Examples 3-4 and 5
When the same experiment as No. 19 was conducted, it was easily peeled off. Example 20 When the composition of Example 2 was sandwiched between two xylene-cleaned aluminum plates and melt-pressed at 250°C, it could not be peeled off by hand. Comparative Examples 18-20 Examples for the compositions of Comparative Examples 3, 4 and 5
When an experiment similar to 20 was conducted, it was easily peeled off. Comparative Example 21 In Example 5, instead of the ethylene-propylene random copolymer rubber, MFI=0.4g/10
Example 5 was carried out in the same manner as in Example 5, except that an ethylene-propylene terpolymer having an ethylene content of 75% by weight and an ethylidenenorbornene content of 0.10% by mole was used. The MFI of the obtained modified polypropylene composition is
9.48g/10 minutes, the amount of grafted maleic anhydride is
The adhesive strength with saponified EVA is 0.238 mol%.
It was 200g/2cm. Furthermore, the obtained coextruded sheet was rough due to gel formation. Comparative Example 22 In Example 2, instead of the ethylene-butene-1 random copolymer rubber, MFI=5.3g/10
Example 2 was carried out in the same manner as in Example 2, except that an ethylene-butene-1-terpolymer having an ethylene content of 80% by weight and an ethylidene norbornene content of 0.15% by mole was used. The obtained modified polypropylene composition
The MFI was 15.1 g/10 min, the amount of grafted maleic anhydride was 0.281 mol%, and the adhesive strength with saponified EVA was 300 g/2 cm. Furthermore, the obtained coextruded sheet was rough due to gel formation. Example 21 20 parts by weight of the composition of Example 2, MFI=1.0g/10
80 parts by weight of homopolypropylene composition L/D
Melt mixing pelletization was performed using a 40 mmφ extruder of =24. Using this composition, coextrusion with saponified EVA was performed in the same manner as in Examples 1 to 16, and the adhesive strength was measured to be 1100 g/2 cm.

Claims (1)

[Scope of Claims] 1 90 to 60 parts by weight of propylene-ethylene block copolymer, 10 to 40 parts by weight of ethylene-α-olefin random copolymer rubber, 0.05 to 5.0 parts by weight of unsaturated carboxylic acid or its derivative, and organic A method for producing a modified polypropylene composition, which comprises melting and kneading a mixture containing 0.01 to 1.0 parts by weight of peroxide. 2 Propylene-ethylene block copolymer
The method according to claim 1, wherein the MFI is from 0.5 to 30 g/10 min and the ethylene content is from 2 to 15 parts by weight. 3 Ethylene-α-olefin copolymer rubber
The method according to claim 1, wherein the MFI is 0.5 to 30 g/10 min and the ethylene content is 50 to 90% by weight. 4. The method according to claim 1, wherein the ethylene-α-olefin copolymer rubber is an ethylene-butene-1 random copolymer rubber. 5. The method according to claim 1, wherein the unsaturated carboxylic acid derivative is maleic anhydride. 6. The method according to claim 1, wherein the amount of the ethylene-α-olefin random copolymer rubber added is 15 to 30 parts by weight relative to 85 to 70 parts by weight of the propylene-ethylene block copolymer.