JPS6239616B2 - - 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 physical properties 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 atactic polypropylene is added (Japanese Patent Application Laid-open No. 90346/1983). However, since a large amount of unreacted monomer remains in the modified polypropylene produced by the melt-kneading method, simply adding atactic polypropylene to the modified polypropylene hardly improves the adhesion. On the other hand, the grafting rate of modified polypropylene produced by the melt-kneading method is generally low, and in order to increase the grafting rate and improve adhesion, a method has been proposed in which a rubber-like substance is added in advance and a melt-kneading reaction is carried out. (For example, Special Publication No. 55-5766, Special Publication No. 55
−18251). However, modified polypropylene produced by the above-mentioned melt-kneading method by adding attic polypropylene in advance also has a large amount of unreacted monomer remaining, and not only does it have insufficient adhesive properties, but it also has poor adhesion properties. It has the disadvantage of generating bubbles during molding. Furthermore, even if the modified polypropylene obtained by adding atactic polypropylene in advance and melt-kneading it is sufficiently heated and degassed, unless the amount of unsaturated carboxylic acid grafted is about 0.15 mol% or more, it becomes a polar substance. Adhesion is not sufficient. In the case of modified polypropylene with an unsaturated carboxylic acid grafting amount of approximately 0.15 mol% or more, heating and degassing can suppress foaming due to unreacted monomers during molding immediately after heating, but unsaturated carboxylic acids are highly hygroscopic. Therefore, if left for a long period of time, it will absorb moisture from the air, causing foaming due to the moisture 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. 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. Surprisingly, after heat-treating modified polypropylene obtained by a melt-kneading method at a temperature of 60°C or higher, 10 to 50 parts by weight of an atactic propylene-ethylene block copolymer was added to 90 to 50 parts by weight of the modified polypropylene. It was discovered that by mixing, a modified polypropylene composition with a low grafting amount of unsaturated carboxylic acid and good adhesiveness can be produced, and the present invention was achieved. The present invention uses 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 comprises mixing 10 to 50 parts by weight of an atactic propylene-ethylene block copolymer to 90 to 50 parts by weight of the modified polypropylene after heat treatment at a temperature of 60°C or higher. be. The modified polypropylene composition obtained by the production method of the present invention can be prepared by simply adding 60% of the modified polypropylene.
Adhesive properties are significantly improved compared to those heat-treated at temperatures above ℃. Although the mechanism of action of the effect of improving adhesion in the present invention is not clear, it is because the modified polypropylene undergoes some structural changes as well as a decrease in unreacted monomers by heat treatment at 60°C or higher. It is assumed that. 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. 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 and 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, and acrylic acid. Glycidyl, glycidyl methacrylate, monoethyl maleate, diethyl maleate, monomethyl fumarate, dimethyl fumarate, monomethyl itaconate, diethyl itaconate, acrylamide, methacrylamide, monoamide maleate, diamide maleate, 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 the unsaturated carboxylic acid or its derivative added is not particularly limited, but is determined depending on the amount of the unsaturated carboxylic acid grafted onto the polypropylene and, ultimately, the amount of the unsaturated carboxylic acid in the modified polypropylene composition. Usually 0.01 to 20 parts by weight, preferably 0.1 parts by weight per 100 parts by weight of polypropylene
Add 5 parts by weight. 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-
Examples include 3-di-t-butyl peroxide, cumene hydroperoxide, and t-butyl hydroperoxide. The amount of organic peroxide added is not particularly limited, but is usually 0.005 to 5 parts by weight, preferably 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 sufficiently mixed in a tumbler, Henschel mixer, etc. The grafting reaction is carried out by melt-kneading at a certain temperature. The method of melt-kneading is not particularly limited, but for example, a screw extruder,
This can be done using a Banbury mixer, mixing roll, etc. The temperature and time of melt-kneading vary depending on the decomposition temperature of the organic peroxide used, but generally 160 to 280°C for 0.3 to 30 minutes, preferably 170 to 250°C for 1 to 10 minutes is appropriate. Note that the melt-kneading may be performed in an inert gas stream. In the present invention, the modified polypropylene produced as described above is heated at a temperature of 60°C or higher, preferably 100°C.
It is important to perform the heat treatment at a temperature of ℃ or higher.
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 heat treatment means may be a conventionally known method, such as an aeration band type dryer, a material stirring type dryer, a fluidized bed dryer, a flash dryer, a spray dryer, a rotary dryer, a drum type dryer,
Although the drying can be carried out using a vacuum dryer, an infrared dryer, a far-infrared dryer, a microwave dryer, etc., a hot air dryer is preferably used. Note that the degassing effect is further improved if heat drying is performed under reduced pressure. The heat treatment time is not particularly limited, but if the heating temperature is low and the modified polypropylene contains a large amount of unreacted monomers, it will take a long time, and if the heating temperature is high and there are few unreacted monomers, it will take a long time. That's fine. Generally, it is preferable to heat and degas for 10 minutes to 10 hours so that the amount of unreacted monomer is 0.05 mol% or less. However, in order to improve the adhesion of the resulting modified polyolefin composition, it is also preferable to perform a heat treatment beyond removing the above-mentioned unreacted monomers. By using the modified polypropylene obtained by such heat treatment, the modified polypropylene composition of the present invention with significantly improved adhesive properties can be obtained. In particular, the modified polypropylene composition of the present invention exhibits good adhesion even when the amount of unsaturated carboxylic acid is 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. Next, in the present invention, it is extremely important to mix an atactic propylene-ethylene block copolymer with the modified polypropylene produced as described above in order to obtain a good modified polypropylene composition of the present invention. . Atactic propylene-ethylene block copolymers generally consist mainly of parts that are soluble in heptane at 60 to 100°C, which are separated as by-products by solvent extraction as atactic parts during the production process of propylene-ethylene block copolymers. The weight average molecular weight is 10,000~
500,000 and the ethylene content is 5~500,000.
Those within the range of 50% by weight are preferably used. Generally, the method for producing propylene-ethylene block copolymers involves polymerizing propylene in the presence of a catalyst containing titanium trichloride and an organoaluminum compound.
There is a two-step polymerization method in which ethylene and propylene are then copolymerized in the presence of the propylene polymer containing the obtained catalyst. Atactic propylene
The ethylene block copolymer is a soluble polymer portion that is extracted with an aliphatic hydrocarbon solvent in the next step from the polymer obtained by these methods. In the present invention, it is necessary to use an atactic propylene-ethylene block copolymer as the atactic polypropylene, and adhesion is not improved even if atactic homopolypropylene and atactic propylene-ethylene random copolymer are used. In the present invention, the amount of the atactic propylene-ethylene block copolymer added is 10 to 50 parts by weight per 90 to 50 parts by weight of modified polypropylene, preferably 15 to 40 parts by weight per 85 to 60 parts by weight.
Parts by weight. If the amount added is less than 10 parts by weight, the effect of improving adhesion is small, and if it exceeds 50 parts by weight, not only the adhesive property but also the mechanical strength decreases, which is not preferable. In addition to modified polypropylene and atactic propylene-ethylene block copolymer, unmodified polypropylene can also be mixed. Addition ratio of unmodified polypropylene to modified polypropylene
0 to 80 parts by weight per 100 to 20 parts by weight, preferably 10 to 80 parts by weight per 90 to 30 parts by weight of modified polypropylene
It is 70 parts by weight. Mixing of modified polypropylene, atactic propylene-ethylene block copolymer, or unmodified polypropylene as required can be carried out using a tumbler, a Henschel mixer, or the like. Further, it is more preferable to melt-knead these mixtures using, for example, a screw extruder, a Banbury mixer, or a mixing roll. The modified polypropylene obtained by the present invention not only has good adhesion to unmodified polypropylene, but also has good adhesion to metals, glass, nylon, polyester, etc.
Shows good adhesion to polar substances such as saponified ethylene-vinyl acetate copolymer. 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 or the like 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 ΓMFI ASTM D 1238−52T
Measured with a load of 2160g. Amount of Γ Maleic Anhydride A film with a thickness of about 0.1 mm was formed by hot pressing, the infrared absorption spectrum was measured, and the amount of maleic anhydride was determined from the absorption peak intensity of maleic anhydride at 1780 cm ^-1 . 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 water and unreacted maleic anhydride was determined by subtracting the amount of graft-reacted maleic anhydride from the total maleic anhydride. Γ Adhesive strength Bonding 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 0.1 part by weight of calcium stearate 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. MFI of the obtained modified polypropylene
The total amount of maleic anhydride was 0.205 mol%, the amount of graft-reacted maleic anhydride was 0.085 mol%, and the amount of unreacted maleic anhydride was 0.120 mol%. This modified polypropylene was heat-treated at 150° C. for 3 hours using a constant temperature hot air dryer. The MFI of the obtained modified polypropylene was 19.5 g/10 min, the total amount of maleic anhydride was 0.101 mol%, the amount of graft-reacted maleic anhydride was 0.081 mol%, and the amount of unreacted maleic anhydride was 0.020 mol%. Next, this modified polypropylene was mixed with a weight average molecular weight of 95,000 and an ethylene content of 22.3 in the proportions shown in Table 1.
% by weight of an atactic propylene-ethylene block copolymer was mixed and melt-kneaded and pelletized at 220°C using a 40 mmφ extruder with L/D=24. Table 1 shows the MFI, maleic anhydride content, adhesive strength with saponified ethylene-vinyl acetate copolymer, and tensile modulus of the obtained modified polypropylene composition. The adhesive strength with the saponified ethylene-vinyl acetate copolymer was determined as follows. That is, the modified polypropylene composition was
At 200℃ from a mmφ extruder, saponified ethylene-vinyl acetate copolymer (MFI = 19.5 g/10 minutes, ethylene content 45 mol%, degree of saponification 99% or more, hereinafter also abbreviated as saponified EVA) was /D=24 30mmφ
Thickness of modified polypropylene composition extruded from extruder through coextrusion T-die at 200 °C, respectively
A coextruded sheet of 0.5 mm thick and 0.2 mm thick of the saponified ethylene-vinyl acetate copolymer was formed, and its T-peel strength was measured. Note that these modified polypropylene compositions did not foam during molding even when left for a long period of time.

[Table] Comparative Example 3 The same procedure as in Example 2 was carried out except that atactic homopolypropylene having a weight average molecular weight of 31,000 was used in place of the atactic propylene-ethylene block copolymer. The MFI of the obtained modified polypropylene composition was 22.5g/10
minutes, the total amount of maleic anhydride was 0.082 mol%, the amount of graft-reacted maleic anhydride was 0.065 mol%, the amount of unreacted maleic anhydride was 0.017 mol%, and the amount of saponified maleic anhydride was 0.017 mol%.
The adhesive strength with EVA was 100 g/2 cm. Comparative Example 4 Same as Example 2 except that an atactic propylene-ethylene random copolymer having a weight average molecular weight of 45,000 and an ethylene content of 4.5% by weight was used in place of the atactic propylene-ethylene block copolymer in Example 2. I did the same thing. The MFI of the obtained modified polypropylene composition was 22.1 g/10 min.
The total amount of maleic anhydride was 0.080 mol%, the amount of graft-reacted maleic anhydride was 0.063 mol%, the amount of unreacted maleic anhydride was 0.017 mol%, and the saponified EVA
The adhesive strength was 100g/2cm. Comparative Example 5 The same procedure as in Example 2 was conducted except that modified polypropylene that was not heat-treated was used. MFI of the obtained modified polypropylene composition
= 27.1 g/10 min, the total amount of maleic anhydride was 0.165 mol%, the amount of graft-reacted maleic anhydride was 0.073 mol%, the amount of unreacted maleic anhydride was 0.092 mol%, and the adhesive strength with saponified EVA was 0. It was hot. It also foamed during molding. Comparative Example 6 MFI=1.3g/10min homopolypropylene 80 parts by weight, weight average molecular weight 95000, ethylene content
20 parts by weight of 22.3% by weight atactic propylene-ethylene block copolymer, 0.3 parts by weight of maleic anhydride
Part by weight, Kayahexa AD-40C0.1 part by weight,
Mix 0.1 part by weight of BTH and 0.1 part by weight of calcium stearate in a Henschel mixer for 5 minutes, and
Melt-kneading pelletization was performed at 220°C using a 40 mmφ extruder of 24, MFI = 17.5 g/10 minutes, total maleic anhydride amount 0.179 mol%, graft reaction maleic anhydride amount 0.127 mol%, unreacted maleic anhydride amount
A 0.52 mol % modified polypropylene composition was obtained.
Next, this modified polypropylene composition was heat-treated at 150°C for 3 hours using a constant temperature air dryer.
MFI=13.8g/10min, total maleic anhydride amount 0.148
A modified polypropylene composition containing 0.125 mol % of graft-reacted maleic anhydride and 0.023 mol % of unreacted maleic anhydride was obtained. The adhesive strength between this modified polypropylene composition and saponified EVA is 0.
It was hot. 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 1.0% by weight ethylene content as polypropylene, 0.5 parts by weight of maleic anhydride, 0.1 parts by weight of dicumyl peroxide,
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,
Melt-kneading pelletization was carried out at 220° C. using a 40 mmφ extruder with L/D=24. The MFI of the obtained modified polypropylene was 3.2 g/10 min, 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
It was 0.117 mol%. This modified polypropylene was heat-treated at 145° C. for 3 hours using a constant temperature hot air dryer. The obtained heat-degassed modified polypropylene
MFI=2.1g/10min, total maleic anhydride amount is 0.110
Mol%, graft reaction maleic anhydride amount is 0.075
mol%, unreacted maleic anhydride amount is 0.035 mol%
It was hot. Next, this heat-treated modified polypropylene 80
Weight average molecular weight 53000, ethylene content in weight parts
20 parts by weight of 15.2% by weight atactic propylene-ethylene block copolymer were mixed, L/D=24
Melt-kneading pelletization was performed at 220°C using a 40mmφ extruder. The MFI of the obtained modified polypropylene composition was 4.5 g/10 min, and the total amount of maleic anhydride was
0.083 mol%, the amount of maleic anhydride in the graft reaction is
The amount of unreacted maleic anhydride was 0.016 mol%. This modified polypropylene composition was
A 40 mmφ extruder was coextruded at 200°C, and nylon 6 was coextruded from a 30 mmφ extruder with L/D=24 at 250°C through a coextrusion T-die to form a modified polypropylene composition layer with a thickness of 0.5 mm and a nylon 6 layer. A coextruded sheet with a thickness of 0.2 mm was molded. The adhesive strength was 2300g/2cm. Comparative Example 7 The same procedure as in Example 6 was carried out except that modified polypropylene which was not heat-treated was used. MFI of the obtained modified polypropylene composition
= 5.4 g/10 minutes, the total amount of maleic anhydride was 0.157 mol%, the amount of graft-reacted maleic anhydride was 0.064 mol%, the amount of unreacted maleic anhydride was 0.093 mol%, and the adhesive strength with nylon 6 was 0. It was hot. Comparative Example 8 MFI=0.5g/10min, 80 parts by weight of propylene-ethylene random copolymer with ethylene content of 1.0% by weight, weight average molecular weight 53000, ethylene content 15.2
Atactic propylene-ethylene block copolymer 20 parts by weight, maleic anhydride 0.3 parts by weight, dicumyl peroxide 0.1 parts by weight, BHT 0.1
Part by weight and 0.1 part by weight of calcium stearate were mixed in a Henschel mixer for 5 minutes, and L/D=
Melt-knead and pelletize with 24 40mmφ extruders,
A modified polypropylene composition was obtained with an MFI of 4.2 g/10 minutes, a total amount of maleic anhydride of 0.205 mol%, an amount of graft-reacted maleic anhydride of 0.136 mol%, and an amount of unreacted maleic anhydride of 0.069 mol%. Next, this modified polypropylene composition was dried using a constant temperature air dryer.
Heat deaeration at 145℃ for 3 hours, MFI=3.7g/10
A modified polypropylene composition was obtained in which the total amount of maleic anhydride was 0.148 mol %, the amount of graft-reacted maleic anhydride was 0.127 mol %, and the amount of unreacted maleic anhydride was 0.021 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 melt-kneaded and pelletized using a 40 mmφ extruder with L/D=24 at 190°C. MFI of the obtained modified polypropylene = 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%. This modified polypropylene was heat-treated at 150℃ for 3 hours using a constant temperature hot air dryer, and MFI = 18.5g/
After 10 minutes, a modified polypropylene containing a total amount of maleic anhydride of 0.110 mol %, an amount of graft-reacted maleic anhydride of 0.080 mol %, and an amount of unreacted maleic anhydride of 0.030 mol % was obtained. Next, 80 parts by weight of this heat-treated modified polypropylene was added with a weight average molecular weight of 235,000 and an ethylene content.
30.5% by weight, 20 parts by weight of atactic propylene-ethylene block copolymer were mixed, L/D=24
Melt-kneading pelletization was performed at 220°C using a 40mmφ extruder. The MFI of the obtained modified polypropylene composition was 13.3 g/10 min, and the total amount of maleic anhydride was
0.085 mol%, the amount of maleic anhydride in the graft reaction is
The amount of unreacted maleic anhydride was 0.019 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 400g/2cm. Comparative Example 9 The same procedure as in Example 7 was carried out except that modified polypropylene which was not heat-treated was used. MFI of the obtained modified polypropylene composition
= 22.5 g/10 minutes, the total amount of maleic anhydride was 0.179 mol%, the amount of graft-reacted maleic anhydride was 0.070 mol%, the amount of unreacted maleic anhydride was 0.109 mol%, and the adhesive strength with polyethylene terephthalate was 0. Ta. Comparative Example 10 MFI=1.2g/10min, 80 parts by weight of propylene-ethylene block copolymer with ethylene content of 2.6%, weight average molecular weight 235000, ethylene content 30.5% by weight
20 parts by weight of atactic propylene-ethylene block copolymer, 0.3 parts by weight of maleic anhydride, 0.2 parts by weight of benzoyl peroxide, 0.1 parts by weight of BHT, and 0.1 parts by weight of calcium stearate were mixed in a Henschel mixer for 5 minutes, and L /D=24 40mm
Melt kneading pelletization was performed at 190℃ using a φ extruder, MFI = 14.3g/10 minutes, total amount of maleic anhydride.
0.203 mol%, graft reaction maleic anhydride amount
A modified polypropylene composition containing 0.148 mol% and an amount of unreacted maleic anhydride of 0.055 mol% was obtained. Next, this modified polypropylene composition was heat-treated at 150°C for 3 hours using a constant-temperature air dryer to reduce the total amount of maleic anhydride at MFI = 12.5 g/10 minutes.
0.152 mol%, graft reaction maleic anhydride amount
A modified polypropylene composition containing 0.135 mol% and an amount of unreacted maleic anhydride of 0.017 mol% was obtained. The adhesive strength between this modified polypropylene composition and polyethylene terephthalate was 100 g/2 cm. 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 11 When the modified polypropylene composition used in Comparative Example 5 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 12 When the same experiment as in Example 9 was conducted on the modified polypropylene composition used in Comparative Example 5,
It was easily peeled off by hand. Comparative Example 13 The modified polypropylene obtained in Example 2 was dissolved in xylene by boiling, and after cooling, it was precipitated with a large amount of acetone, filtered, and then dried under reduced pressure at 50° C. for 24 hours. The MFI of this modified polypropylene (A) was 21.5 g/10 min, the total amount of maleic anhydride was 0.108 mol%, the amount of graft-reacted maleic anhydride was 0.081 mol%, and the amount of unreacted maleic anhydride was 0.027 mol%. . Next, 80 parts by weight of modified polypropylene (A), 20 parts by weight of an atactic propylene-ethylene block copolymer having a weight average molecular weight of 95,000 and an ethylene content of 22.3% by weight, 0.1 part by weight of BHT and 0.1 part by weight of calcium stearate were added. 5 with Ciel Mixer
Mix for 220 minutes using a 40mmφ extruder with L/D=24.
Pelletization was performed at ℃ to obtain a modified polypropylene composition with MFI = 23.5 g/10 min, total maleic anhydride amount of 0.083 mol%, graft reaction maleic anhydride amount of 0.066 mol%, and unreacted maleic anhydride amount of 0.017 mol%. . It was determined in the same manner as in Example 2. The adhesive strength between this composition and saponified EVA was 100 g/2 cm. Comparative Example 14 Comparative Example 13 cm ² The obtained modified polypropylene (A) was extracted with acetone for 8 hours using a Soxhlet extractor, and 50
Modified polypropylene (B) was dried under reduced pressure for 24 hours at °C to obtain a modified polypropylene (B) with MFI = 19.0 g/10 min, total maleic anhydride amount of 0.082 mol%, graft reaction maleic anhydride amount of 0.079 mol%, and unreacted maleic anhydride amount of 0.003 mol%. I got it. Next, 80 parts by weight of modified polypropylene (B), 20 parts by weight of an atactic propylene-ethylene block copolymer having a weight average molecular weight of 95,000 and an ethylene content of 22.3% by weight, 0.05 parts by weight of maleic anhydride,
0.1 parts by weight of BHT and 0.1 parts by weight of calcium stearate
Mix the weight parts with a hexyl mixer for 5 minutes, and
Pelletization was performed at 220°C using a 40 mmφ extruder with D = 24, MFI = 22.1 g/10 minutes, total maleic anhydride amount 0.082 mol%, graft reaction maleic anhydride amount 0.066 mol%, unreacted maleic anhydride amount 0.016. A modified polypropylene composition of mol % was obtained. It was determined in the same manner as in Example 2. This composition and saponification
The adhesive strength with EVA was 100 g/2 cm. Comparative Example 15 The same procedure as Comparative Example 14 was carried out except that maleic anhydride was not added. MFI of the obtained modified polypropylene composition = 21.8g/10
The total amount of maleic anhydride was 0.067 mol%, the amount of graft-reacted maleic anhydride was 0.064 mol%, and the amount of unreacted maleic anhydride was 0.003 mol%, which were determined in the same manner as in Example 2. This composition and saponification
The adhesive strength with EVA was 1300 g/2 cm. Table 2 below shows Example 2 and Comparative Examples 13, 14 and 15.
The results are also shown.

【table】

【table】

Claims (1)

[Claims] 1. Modified polypropylene obtained by melt-kneading a mixture of polypropylene, an unsaturated carboxylic acid or its derivative, and an organic peroxide is heated at a temperature of 60°C or higher, and then the modified polypropylene 90 1. A method for producing a modified polypropylene composition, which comprises mixing 10 to 50 parts by weight of an atactic propylene-ethylene block copolymer to 50 parts by weight. 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 is heated and degassed so that the residual unreacted monomer in the modified polypropylene is 0.05 mol% or less. 5. The method according to claim 1, wherein the atactic propylene-ethylene block copolymer has a weight average molecular weight of 10,000 to 500,000 and an ethylene content of 5 to 50% by weight. 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.