JPS6239615B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing modified polypropylene that has good adhesion to polar substances such as polyolefins, nylon, polyester, saponified ethylene-vinyl acetate copolymers, glass, and metals. In general, polypropylene has mechanical properties, transparency,
It is used in a wide range of fields because of its excellent moldability and sanitary properties, but it has the disadvantage of poor adhesion to polar substances because it is nonpolar. Various proposals have been made to improve this adhesiveness, one of which is a method of grafting a monomer consisting of an unsaturated carboxylic acid or a derivative thereof to polypropylene. The method of grafting is to react in a solution state (for example,
-15422), a method of reacting in a slurry state (for example, Japanese Patent Publication No. 43-18144), and a method of reacting in a molten state (for example, Japanese Patent Publication No. 43-27421). Among these methods, the method of reacting in a molten state using an extruder is advantageous because it is easy to operate, but unreacted monomer remains in the obtained modified polypropylene, and if there is a large amount of it, it may cause adhesion. There are disadvantages such as insufficient properties and the generation of bubbles during molding of sheets, films, blow molding, etc. Therefore, methods for removing unreacted monomers include the dissolution-reprecipitation method and the solvent extraction method (Japanese Patent Application Laid-Open No. 1983-99193).
However, these methods require the use of large amounts of solvents and poor solvents, are complicated to operate, and have the drawbacks of high costs. The present inventors previously conducted various studies on methods for removing unreacted monomers remaining in modified polypropylene obtained by a melt-kneading method using unsaturated carboxylic acids or derivatives thereof, and found that By heating modified polypropylene at 60°C or higher, unreacted monomers are significantly reduced, foaming phenomenon during sheet, film, blow molding, etc. is suppressed, and adhesion with polar substances is improved. I found it (patent application 1972-170896)
issue). On the other hand, in order to improve the adhesion of modified polypropylene grafted with unsaturated carboxylic acids, a method has been proposed in which a soft polymer such as low-density polyethylene or ethylene-vinyl acetate copolymer is added to the modified polypropylene. (For example, Tokuko Sho 54-
No. 40113, Japanese Patent Publication No. 53-16781). however,
Modified polypropylene produced by the melt-kneading method contains a large amount of residual reactive monomers, so
Simply adding low density polyethylene or the like to this will hardly improve the adhesion. On the other hand, since modified polypropylene produced by the melt-kneading method generally has a low grafting rate, a method has been proposed in which a rubber-like substance is added in advance to improve the grafting rate by the melt-kneading reaction to improve adhesion (for example, Publication No. 55-5766, Special Publication No. 55-
No. 18251). However, modified polypropylene produced by the above-mentioned melt-kneading reaction with the addition of low-density polyethylene in the same way has a large amount of unreacted monomer remaining, and not only does it have insufficient adhesive properties, but also It has the disadvantage of generating air bubbles during molding. In addition, even if the modified polypropylene obtained by melt-kneading with low density polyethylene added in advance is heated and degassed sufficiently, if the amount of unsaturated carboxylic acid grafted is not about 0.15 mol% or more, it will not interact with polar substances. Adhesion is not sufficient. If the amount of unsaturated carboxylic acid grafted is approximately 0.15 mol or more, foaming due to unreacted monomers during molding immediately after heating can be suppressed by heating, but unsaturated carboxylic acids are highly hygroscopic and should not be left for a long period of time. If left for a long time, it will absorb moisture from the air, causing foaming during molding. Therefore, there has been a desire for a modified polypropylene that does not cause foaming during molding due to moisture absorption, has a low grafting amount of unsaturated carboxylic acid, and has good adhesion to polar substances. In view of the above, the present inventors conducted various studies on a method for producing modified polypropylene that has a low grafting amount of unsaturated carboxylic acid and has good adhesion to polar substances using a melt-kneading method that is easy to operate and inexpensive. As a result, surprisingly, by mixing 10-50 parts by weight of low-density polyethylene with 90-50 parts by weight of modified polypropylene obtained by the melt-kneading method and heat-treating the mixture at a temperature of 60°C or higher, unsaturated The inventors have discovered that it is possible to produce a modified polypropylene composition with a low grafting amount of carboxylic acid and excellent adhesion, and have arrived at the present invention. The present invention is a modified polypropylene 90 obtained by melt-kneading a mixture of polypropylene, an unsaturated carboxylic acid or its derivative, and an organic peroxide.
This is a method for producing a modified polypropylene composition, which comprises mixing 10 to 50 parts by weight of low-density polyethylene to 50 parts by weight, and then heat-treating the mixture at a temperature of 60°C or higher. The modified polypropylene composition obtained by the production method of the present invention can be prepared by simply adding 60% of the modified polypropylene.
Adhesion is significantly improved compared to compositions that have been heat treated at temperatures above 0.degree. C. or compositions that have been melt-kneaded by simply adding low-density polyethylene to modified polypropylene. The mechanism of action of the adhesion-improving effect of the present invention is not clear, but it is believed that the modified polypropylene composition in particular undergoes some structural changes as well as a decrease in unreacted monomers by heat treatment at 60°C or higher. Guessed. Therefore, it is also effective to perform heat treatment at 60° C. or higher for more than just reducing unreacted monomers. The polypropylene used in the present invention is not particularly limited, and includes homopolypropylene, propylene-ethylene random copolymer, propylene-ethylene block copolymer, copolymer of propylene and α-olefin, and mixtures thereof. used. In addition, 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, and examples of unsaturated carboxylic acid derivatives include acid anhydrides, There are esters, 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, monoethyl maleate, diethyl maleate, monomethyl fumarate, dimethyl fumarate, Itacon Acid monomethyl ester, itaconic acid diethyl ester, acrylamide, methacrylamide, maleic acid monoamide, maleic acid diamide, maleic acid-N-monoethylamide, 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-monobutylamide, fumaric acid-N/N-dibutylamide, maleimide, N-butylmaleimide, N-phenylmaleimide, sodium acrylate, sodium methacrylate, potassium acrylate, potassium methacrylate, etc. can be mentioned. Of these,
Most preferably maleic anhydride is used. The amount of unsaturated carboxylic acid or its derivative added is not particularly limited, but may be determined depending on the amount of graft reaction of unsaturated carboxylic acid to polypropylene and the amount of unsaturated carboxylic acid in the modified polypropylene composition. It is usually added in an amount of 0.01 to 20 parts by weight, preferably 0.1 to 5 parts by weight, per 100 parts by weight of polypropylene. Further, in the present invention, an organic peroxide is used to promote the reaction between polypropylene and an unsaturated carboxylic acid or a derivative thereof. 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)hexane, 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 not particularly limited, but is usually 0.005 to 5 parts by weight,
Preferably it is 0.01 to 1 part by weight. Furthermore, in the present invention, fillers such as talc, calcium carbonate, gypsum, and magnesium oxide; butylated hydroxytoluene, butylated hydroxyanisole, tetrakis[methylene-3(3.5
-di-t-butyl-4-hydroxy-fumanyl)
[propionate] heat stabilizers such as methane; weather stabilizers; lubricants; antistatic agents; nucleating agents; pigments; dyes;
It may also contain an antiblocking agent. In the present invention, the above-mentioned polypropylene, unsaturated carboxylic acid or its derivative, and organic peroxide are thoroughly mixed in a tumbler, Henschel mixer, etc., and the mixture is heated above the melting point of polypropylene, generally above the melting point and below 280°C. The grafting reaction is carried out by melt-kneading at a temperature of . 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 in general, it is appropriate to do it at 160 to 280°C for 0.3 to 30 minutes, preferably at 170 to 250°C for 1 to 10 minutes.
Note that the melt-kneading may be performed in an inert gas stream. Next, in the present invention, it is necessary to mix low density polyethylene with the modified polypropylene produced as described above. The low density polyethylene used in the present invention is not particularly limited,
MFI0.1~100g/10min, preferably 0.5~30
g/10 min, specific gravity 0.915 to 0.940, preferably 0.915
A value of 0.925 to 0.925 is preferable. In the present invention, the amount of low density polyethylene added is based on 90 to 50 parts by weight of modified polypropylene.
10 to 50 parts by weight, preferably 15 to 40 parts by weight, preferably 85 to 60 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, transparency, etc. decrease. In addition to modified polypropylene and low density polyethylene, unmodified polypropylene can also be mixed. The proportion of unmodified polypropylene added is 0 to 80 parts by weight per 100 to 20 parts by weight of modified polypropylene, preferably 10 to 70 parts by weight per 90 to 30 parts by weight of modified polypropylene. Mixing of modified polypropylene, low density polyethylene, or unmodified polypropylene as necessary can be carried out using a tumbler, Henschel mixer, or the like. Next, these mixtures are melt-kneaded using, for example, a screw extruder, a Banbury mixer, or a mixing roll. Such melt-kneading corresponds to the heat treatment at 60° C. or higher in the present invention, and unreacted monomers may be removed simultaneously with the kneading. Furthermore, in the present invention, it is extremely important to heat and degas the modified polypropylene composition produced as described above at a temperature of 60°C or higher, preferably 100°C or higher. That is, by such heat treatment, the adhesiveness of the modified polypropylene composition of the present invention is significantly improved compared to conventional modified polypropylene compositions. In particular, the modified polypropylene composition of the present invention exhibits good adhesion even when the amount of unsaturated carboxylic acid grafted is, for example, about 0.15 mol % or less, particularly 0.12 mol % or less, which does not cause foaming during molding. Therefore, according to the present invention, there is provided a modified polyolefin composition that does not cause foaming during molding and has good adhesive properties. If the heating temperature is below 60°C, degassing takes a long time and is not practical. Although the upper limit of the heating temperature is not particularly limited, it is preferably below the melting point of the modified polypropylene in order to prevent fusion of the modified polypropylene. The heating degassing means may be a conventionally known method, such as an aeration band type dryer, a material agitation type dryer, a fluidized bed dryer, a flash dryer,
The drying can be carried out using a spray dryer, a rotary dryer, a drum type dryer, a vacuum dryer, an infrared dryer, a far-infrared dryer, a microwave dryer, etc., but a hot air dryer is preferably used. Note that the degassing effect is further improved if heat drying is performed under reduced pressure. The heating deaeration time is not particularly limited, but it may take a long time if the heating temperature is low and the modified polypropylene contains a large amount of unreacted monomers, and it may take a short time if the heating temperature is high and there are few unreacted monomers. That's fine. Generally, the time is 10 minutes to 10 hours, and it is preferable to heat and degas so that the amount of unreacted monomer is 0.05 mol% or less. The modified polypropylene composition obtained in 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, and saponified ethylene-vinyl acetate copolymers. Shows adhesion. Therefore, for example, (1) polar resin/modified polypropylene composition/polypropylene, (2) modified polypropylene composition/polar resin/modified polypropylene composition/polypropylene, (3) polypropylene/modified polypropylene composition/polar resin/modified. It is possible to provide a laminate of polypropylene composition/polypropylene with good adhesiveness. Further, when these laminates are stretched, a composite stretched polypropylene film having excellent gas barrier properties, oil resistance, water impermeability and heat sealability is obtained. EXAMPLES 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. At 230℃ by ΓMEI ASTM D 1238−52T
Measured with a load of 2160g. Amount of Γ maleic anhydride A film with a thickness of approximately 0.1 mm was formed by hot pressing, the infrared absorption spectrum was measured, and from the absorption peak intensity of maleic anhydride at 1780 cm ^-1 , Polymer Chemistry, Vol. 25, No. 274 (1968 The amount of maleic anhydride was quantified using the calibration curve shown in Fig. 2 on page 109 of 2010. The amount of maleic anhydride in the graft reaction was defined as the amount of maleic anhydride in a sample obtained by extracting a film with a thickness of about 0.1 mm for 6 hours with acetone and then drying it under vacuum at a temperature of 50° C. for 24 hours. The amount of residual unreacted maleic anhydride was determined by subtracting the amount of graft-reacted maleic anhydride from the total amount of maleic anhydride. Γ Adhesive strength (T-peel strength) Adhesion between saponified ethylene-vinyl acetate copolymer, nylon and polyethylene terephthalate is achieved by co-extruding both, and after cooling and solidifying, the width is 2 mm in the longitudinal direction.
It was cut into cm pieces and the T-peel strength was measured. Adhesion to glass and aluminum was determined by wiping the glass plate and aluminum plate with xylene, sandwiching modified polypropylene between the two plates, melting at 250℃, pressing, cooling and solidifying, and peeling off by hand. The adhesive strength was measured by looking at the sample. A T-die is attached to a 40 mmφ extruder with Γ tensile modulus L/D = 20, and a sheet with a thickness of 0.5 mm is extruded at 200°C. The obtained sheet is cut into strips with a width of 1 cm in the MD direction, and then stretched A tensile test was conducted using a testing machine at a chuck distance of 5 cm and a tensile speed of 20 mm/min, and the tensile modulus was calculated from the initial slope. Examples 1 to 4, Comparative Examples 1 to 2 MFI = 1.3 g/10 min homopolypropylene 100 parts by weight, maleic anhydride 0.5 parts by weight, 2,5-dimethyl-2,5-di(t-butylperoxy) Hexane (trade name; Kayahexa AD-40C) 0.1 part by weight, butylated hydroxytoluene (trade name;
BHT) 0.1 part by weight and calcium stearate 0.1 part by weight were mixed in a Henschel mixer for 5 minutes, and L/
Melt-kneading pelletization was carried out at 220° C. using a D=24 40 mmφ extruder. The MFI of the obtained modified polypropylene was 33.1 g/10 min, and the total amount of maleic anhydride was
0.205 mol%, the amount of maleic anhydride in the graft reaction is
The amount of unreacted maleic anhydride was 0.120 mol%. Next, low-density polyethylene with a specific gravity of 0.919 and MFI = 15.1 g/10 min was mixed with this modified polypropylene in the proportions shown in Table 1, and 40
Melt-kneading pelletization was performed at 220°C using a mmφ extruder. Thereafter, these modified polypropylene compositions were heated and degassed at 150° C. for 3 hours using a constant temperature air dryer. The obtained modified polypropylene composition
Table 1 shows MFI, maleic anhydride content, adhesive strength with saponified ethylene-vinyl acetate copolymer (hereinafter also abbreviated as saponified EVA), and tensile modulus. The adhesive strength with the saponified ethylene-vinyl acetate copolymer was determined as follows. That is, a modified polypropylene composition was heated at 200°C from a 40 mmφ extruder with L/D = 20, and a saponified ethylene-vinyl acetate copolymer (MFI = 19.5 g/10 min, ethylene content 45 mol%, degree of saponification 99). % or more) L/D=24
Co-extruded at 200℃ from a 30mmφ extruder
The modified polypropylene composition was extruded through a die to form coextruded sheets with a thickness of 0.5 mm and the saponified ethylene-vinyl acetate copolymer with a thickness of 0.2 mm.
- Peel strength was measured. Note that these modified polypropylene compositions did not foam during molding even when left for a long time.

[Table] Comparative Example 3 The same procedure as in Example 2 was carried out except that heating deaeration was not performed in Example 2. MFI of the obtained modified polypropylene composition was 25.6 g/10 min, the total amount of maleic anhydride was 0.151 mol%, the amount of graft-reacted maleic anhydride was 0.070 mol%, and the amount of unreacted maleic anhydride was 0.081 mol%, The adhesive strength with saponified EVA was 0. It also foamed during molding. Comparative Example 4 MFI=1.3g/10min homopolypropylene 80 parts by weight, specific gravity 0.919, MFI=15.1g/10min low density polyethylene 20 parts by weight, maleic anhydride 0.3 parts by weight, Kayahexa AD-40C 0.1 parts by weight , 0.1 part by weight of BHT, and 0.1 part by weight of calcium stearate were mixed in a Henschel mixer for 5 minutes, and 40
Melt kneading pelletization was performed at 220℃ using a mmφ extruder, MFI = 16.3g/10 minutes, total amount of maleic anhydride.
0.168 mol%, graft reaction maleic anhydride amount
A modified polypropylene composition containing 0.121 mol% and an amount of unreacted maleic anhydride of 0.047 mol% was obtained. Then,
This modified polypropylene composition was heated and degassed at 150°C for 3 hours using a constant temperature hot air dryer, and MFI=
A modified polypropylene composition having a total amount of maleic anhydride of 0.146 mol%, a graft reaction amount of maleic anhydride of 0.121 mol%, and an amount of unreacted maleic anhydride of 0.025 mol% was obtained. The adhesive strength between this modified polypropylene composition and saponified EVA was 0. When this modified polypropylene was left for 5 months, small bubbles were generated during molding. Example 6 MFI=0.5 g/10 min, 100 parts by weight of propylene-ethylene random copolymer with ethylene content of 1.0% by weight, 0.5 parts by weight of maleic anhydride, 0.1 parts by weight of digyl peroxide, 0.1 parts by weight of BHT, and Stair 0.1 part by weight of calcium phosphate was mixed for 5 minutes using a Henschel mixer, and melt-kneaded and pelletized at 220°C using a 40 mmφ extruder with L/D=24. MFI of the obtained modified polypropylene = 3.2 g/10 minutes,
The total amount of maleic anhydride was 0.203 mol%, the amount of graft-reacted maleic anhydride was 0.086 mol%, and the amount of unreacted maleic anhydride was 0.117 mol%. 80 parts by weight of this modified polypropylene, specific gravity 0.924, MFI=7.0
20 parts by weight of low-density polyethylene of 20 g/10 min were mixed and melt-kneaded and pelletized at 220° C. using a 40 mmφ extruder with L/D=24. Next, this modified polypropylene composition was dried at 145% using a constant temperature air dryer.
The mixture was heated and degassed at ℃ for 3 hours. The MFI of the obtained modified polypropylene composition was 3.3 g/10 min, the total amount of maleic anhydride was 0.085 mol%, the amount of graft-reacted maleic anhydride was 0.071 mol%, and the amount of unreacted maleic anhydride was 0.014 mol%. . This modified polypropylene composition was heated to 200 mm from a 40 mmφ extruder with L/D=20.
℃, and nylon 6 was coextruded through a coextrusion T-die at 250℃ from a 30 mmφ extruder with L/D=24, and the thickness of the modified polypropylene composition layer was determined.
A coextruded sheet with a thickness of 0.5 mm and 6 layers of nylon and a thickness of 0.2 mm was molded. The adhesive strength was 4700g/2cm. Comparative Example 5 The same procedure as in Example 6 was carried out except that heating deaeration was not performed in Example 6. The MFI of the obtained modified polypropylene composition was 3.7 g/10 min, the total amount of maleic anhydride was 0.183 mol%, the amount of graft-reacted maleic anhydride was 0.070 mol%, and the amount of unreacted maleic anhydride was 0.113 mol%, The adhesive strength with nylon 6 was 0. Comparative Example 6 MFI=0.5g/10min, 80 parts by weight of propylene-ethylene random copolymer with ethylene content of 1.0% by weight, specific gravity 0.924, 20 parts by weight of low-density polyethylene with MFI=7.0g/10min, maleic anhydride 0.3 weight part,
0.1 part by weight of dicumyl peroxide, 0.1 part by weight of BHT and 0.1 part by weight of calcium stearate were mixed in a Henschel mixer for 5 minutes, and L/D = 24.
Melt kneading pelletization is performed using a 40mmφ extruder, and MFI
=2.3g/10min, total amount of maleic anhydride 0.195 mol%, graft reaction maleic anhydride 0.140 mol%,
A modified polypropylene composition containing 0.055 mol % of unreacted maleic anhydride was obtained. Next, this modified polypropylene composition was dried at 145% using a constant temperature air dryer.
Heat and degas at ℃ for 3 hours, MFI=2.1g/10
A modified polypropylene composition was obtained in which the total amount of maleic anhydride was 0.153 mol %, the amount of graft-reacted maleic anhydride was 0.135 mol %, and the amount of unreacted maleic anhydride was 0.018 mol %. The adhesive strength between this modified polypropylene composition and nylon 6 was 100 g/2 cm. Example 7 MFI = 1.2 g/10 min, 100 parts by weight of propylene-ethylene block copolymer with ethylene content of 2.6% by weight, 0.5 parts by weight of maleic anhydride, 0.2 parts by weight of benzoyl peroxide, 0.1 parts by weight of BHT, calcium stearate. 0.1 part by weight was mixed for 5 minutes using a Henschel mixer, and then mixed using a 40 mm extruder with L/D = 24.
Melt-kneading pelletization was performed at 190°C. The MFI of the obtained modified polypropylene was 30.5 g/10 minutes, the total amount of maleic anhydride was 0.233 mol%, the amount of graft-reacted maleic anhydride was 0.092 mol%, and the amount of unreacted maleic anhydride was 0.141 mol%. 80 parts by weight of this modified polypropylene, specific gravity 0.920, MFI=2.7g/
Mix 20 parts by weight of low density polyethylene for 10 minutes;
Melt-kneading pelletization was performed at 220° C. using a 40 mmφ extruder with L/D=24. Next, this modified polypropylene composition was heated and degassed at 150°C for 3 hours using a constant temperature hot air dryer, MFI = 11.8 g/10 minutes, total maleic anhydride amount 0.089 mol%, graft reaction maleic anhydride amount. A modified polypropylene composition was obtained in which the amount of unreacted maleic anhydride was 0.073 mol % and the amount of unreacted maleic anhydride was 0.016 mol %. This modified polypropylene composition was
At 200℃ from a 40mmφ extruder, and polyethylene terephthalate from a 30mmφ extruder with L/D=24.
Extruded through coextrusion T-die at 270℃, modified polypropylene composition layer thickness 0.5mm,
A coextruded sheet with a polyethylene terephthalate layer of 0.2 mm thickness was made and the adhesive strength was measured.
It was 700g/2cm. Comparative Example 7 The same procedure as in Example 7 was carried out except that heating deaeration was not performed in Example 7. MFI of the obtained modified polypropylene composition was 20.1 g/10 min, the total amount of maleic anhydride was 0.182 mol%, the amount of graft-reacted maleic anhydride was 0.072 mol%, and the amount of unreacted maleic anhydride was 0.110 mol%, The adhesive strength with polyethylene terephthalate was zero. Comparative Example 8 MFI = 1.2 g/10 min, 80 parts by weight of propylene-ethylene block copolymer with ethylene content of 2.6%, specific gravity 0.920, 20 parts by weight of low density polyethylene with MFI = 2.7 g/10 min, 0.3 weight of maleic anhydride. parts, benzoyl peroxide 0.2 parts by weight, BHT 0.1 parts by weight,
0.1 part by weight of calcium stearate was mixed in a Henschel mixer for 5 minutes, melt-kneaded and pelletized at 190°C using a 40mmφ extruder with L/D=24.
MFI=12.8g/10min, total maleic anhydride amount 0.206
A modified polypropylene composition containing 0.150 mol% of graft-reacted maleic anhydride and 0.056 mol% of unreacted maleic anhydride was obtained. Next, this modified polypropylene composition was dried using a constant temperature air dryer.
Heat deaeration at 150℃ for 3 hours, MFI=10.1g/
After 10 minutes, a modified polypropylene composition was obtained in which the total amount of maleic anhydride was 0.163 mol%, the amount of graft-reacted maleic anhydride was 0.148 mol%, and the amount of unreacted maleic anhydride was 0.015 mol%. The adhesive strength between this modified polypropylene composition and polyethylene terephthalate is
It was 100g/2cm. Example 8 The modified polypropylene composition used in Example 2 was sandwiched between two glass plates wiped with xylene, melted and pressed at 250°C, and cooled and solidified. This material could not be peeled off by hand. Comparative Example 9 When the modified polypropylene composition used in Comparative Example 3 was subjected to the same experiment as in Example 8, it was easily peeled off by hand. Example 9 The modified polypropylene composition used in Example 2 was sandwiched between two xylene-wiped aluminum plates, melted and pressed at 250°C, and cooled and solidified.
This material could not be peeled off by hand. Comparative Example 10 When the same experiment as in Example 9 was conducted on the modified polypropylene composition used in Comparative Example 3,
It was easily peeled off by hand. Comparative Example 11 The modified polypropylene composition obtained in Comparative Example 3 was dissolved in xylene by boiling, and after cooling, it was precipitated with a large amount of acetone, and then dried under reduced pressure at 50° C. for 24 hours. MFI of this modified polypropylene composition (A) = 20.3g/
After 10 minutes, the total amount of maleic anhydride was 0.081 mol%, the amount of graft-reacted maleic anhydride was 0.068 mol%, and the amount of unreacted maleic anhydride was 0.013 mol%. Next, 100 parts by weight of modified polypropylene composition (A),
0.1 part by weight of BHT and 0.1 part by weight of calcium stearate were mixed in a Henschel mixer for 5 minutes, and L/D
Saponification obtained in the same manner as in Example 2 after pelletizing at 220°C with a 40 mmφ extruder of =24
The adhesive strength with EVA was 300 g/2 cm. Comparative Example 12 The modified polypropylene composition (A) obtained in Comparative Example 11 was extracted with acetone using a Soxhlet extractor for 8 hours, and dried under reduced pressure at 50°C for 24 hours to obtain an MFI of 19.2 g/10.
A modified polypropylene composition (B) having a total amount of maleic anhydride of 0.069 mol %, a graft reaction amount of maleic anhydride of 0.066 mol %, and an amount of unreacted maleic anhydride of 0.003 mol % was obtained. Next, the modified polypropylene composition
(B) 100 parts by weight, maleic anhydride 0.05 parts by weight,
0.1 parts by weight of BHT and 0.1 parts by weight of calcium stearate
Mix the weight parts in a Henschel mixer for 5 minutes,
Pelletization was performed at 220°C using a 40 mmφ extruder with L/D = 24, MFI = 19.9 g/10 min, total maleic anhydride amount 0.081 mol%, graft reaction maleic anhydride amount 0.067 mol%, unreacted maleic anhydride amount 0.014
A modified polypropylene composition of mol % was obtained. This composition and saponification obtained in the same manner as in Example 2
The adhesive strength with EVA was 100 g/2 cm. Comparative Example 13 The same procedure as Comparative Example 12 was conducted except that maleic anhydride was not added. The adhesive strength between the obtained modified polypropylene composition and saponified EVA was 2100 g/2 cm. Table 2 below shows Example 2 and Comparative Examples 11, 12 and
The results of 13 are also shown.

【table】

【table】

Claims (1)

[Scope of Claims] 1. 10 to 50 parts by weight of low-density polyethylene mixed with 90 to 50 parts by weight of modified polypropylene obtained by melt-kneading a mixture of polypropylene, an unsaturated carboxylic acid or its derivative, and an organic peroxide. A method for producing a modified polypropylene composition, which is then heat-treated at a temperature of 60°C or higher. 2. The method according to claim 1, wherein the unsaturated carboxylic acid derivative is maleic anhydride. 3. The method according to claim 1, wherein the heating temperature is 100°C or higher and lower than the melting point of the modified polypropylene. 4. The method according to claim 1, wherein the modified polypropylene composition is heated and degassed so that the residual unreacted monomer in the modified polypropylene composition is 0.05 mol% or less. 5 Low density polyethylene has MFI0.5~30g/10
Claim 1, which has a specific gravity of 0.915 to 0.940.
The method described in section. 6 Modified polypropylene contains 100 parts by weight of polypropylene and 0.05 to 0.05 parts of unsaturated carboxylic acid or its derivative.
The method according to claim 1, wherein the modified polypropylene is obtained by melt-kneading a mixture consisting of 5 parts by weight and 0.01 to 1 part by weight of an organic peroxide.