JPS634868B2 - - 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 the amount is large, the adhesive property There are drawbacks such as insufficient oxidation and the generation of bubbles during molding of sheets, films, blow molding, etc. Therefore, methods for removing unreacted monomers include dissolution-reprecipitation method and solvent extraction method (Japanese Patent Application Laid-open No. 54-99193).
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. Found (Unexamined Japanese Patent Publication No. 56-95914)
issue). On the other hand, in order to improve the adhesion of modified polypropylene grafted with unsaturated carboxylic acids, a method of adding soft polymers such as low density polyethylene or rubber substances has been proposed (for example,
No. 40112, Special Publication No. 1983-40113, No. 80334 of Special Publication No. 1987-80334
(No. 16781, Japanese Patent Publication No. 53-16781). However, since a large amount of unreacted monomer remains in the modified polypropylene produced by the melt-kneading method, simply adding a soft polymer to the modified polypropylene will hardly improve 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
- No. 18251). However, modified polypropylene produced by the above-mentioned melt-kneading reaction with the addition of a soft polymer 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. In addition, the modified polypropylene obtained by adding a soft polymer in advance and melt-kneading has a graft amount of unsaturated carboxylic acid of about 0.15 mol% even if it is sufficiently heated and deaerated.
Otherwise, the adhesion to polar substances will not be sufficient.
If the amount of unsaturated carboxylic acid grafted is approximately 0.15 mol% or more, heating and deaeration can suppress foaming due to unreacted monomers during molding immediately after heating, but unsaturated carboxylic acid has strong hygroscopicity and will not last for a long time. If left untreated, it absorbs moisture from the air and foams due to 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 have previously 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. After heat-treating the modified polypropylene obtained by the melt-kneading method at a temperature of 60°C or higher, 90 to 50 parts by weight of the modified polypropylene is added with 10 to 50 parts by weight of ethylene-α-olefin copolymer or low density polyethylene.
It was discovered and proposed that by mixing parts by weight, it is possible to produce a modified polypropylene composition with a low grafting amount of unsaturated carboxylic acid and good adhesiveness (Japanese Patent Application No. 140592-1983,
- No. 157023). In addition, 90 to 50 parts by weight of modified polypropylene obtained by the melt-kneading method was added with ethylene-α.
-Olefin copolymer or low density polyethylene
It was discovered and proposed that a modified polypropylene composition with a low grafting amount of unsaturated carboxylic acid and good adhesiveness can be produced by mixing 10 to 50 parts by weight and heat-treating the mixture at a temperature of 60°C or higher. (Special application No. 140593, Patent application No. 157024)
issue). However, the modified polypropylene compositions produced by these methods still have insufficient adhesive strength under severe adhesive conditions, ie, under conditions where the adhesive layer and adherent layer are thin and are rapidly cooled after melt lamination. The present inventors have conducted various studies on a method for producing modified polypropylene that has a low grafting amount of unsaturated carboxylic acids using a melt-kneading method and has even better adhesion to polar substances even under severe adhesion conditions. The inventors have discovered that the intended purpose can be achieved through treatment, and have arrived at the present invention. That is, in the present invention, a 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 95-50 5 to 5 parts by weight of ethylene polymer
This is a method for producing a modified polypropylene composition, which is characterized in that 50 parts by weight are mixed, melt-kneaded, and then heat-treated again at a temperature of 60° C. or higher. The modified polypropylene composition obtained by the production method of the present invention is obtained by simply heat-treating modified polypropylene obtained by a melt-kneading method at a temperature of 60°C or higher, or by simply adding an ethylene polymer to modified polypropylene. Adhesion is higher than that of polypropylene, modified polypropylene that has been heat-treated at a temperature of 60°C or higher and an ethylene polymer added to it, and modified polypropylene that has an ethylene polymer added and then heat-treated at a temperature of 60°C or higher. performance is greatly improved. 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 unsaturated carboxylic acids added is not particularly limited, but is determined depending on the amount of unsaturated carboxylic acids grafted onto polypropylene and, ultimately, the amount of unsaturated carboxylic acids 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 unsaturated carboxylic acids. 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-butylperoxide, cumene hydroperoxide,
Examples include 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-
It may contain a heat stabilizer such as di-t-butyl-4-hydroxy-fumanyl propionate (methane), a weather stabilizer, a lubricant, an antistatic agent, a nucleating agent, a pigment, a dye, an antiblocking agent, and the like. In the present invention, the polypropylene, unsaturated carboxylic acids, and organic peroxide shown above are thoroughly mixed in a tumbler, Henschel mixer, etc.
Above the melting point of polypropylene, generally above the melting point
The grafting reaction is carried out by melt-kneading at a temperature of 280°C or lower. The melt-kneading method is not particularly limited, and can be carried out using, for example, a screw extruder, a Banbury mixer, a mixing roll, etc., but a screw extruder is preferably used. The temperature and time of melt kneading vary depending on the decomposition temperature of the organic peroxide used, but is 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.
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 heating and degassing means can be carried out using conventionally known methods such as ventilation band dryers, material agitation dryers, fluidized bed dryers, flash dryers, spray dryers, rotary dryers, drum dryers, vacuum dryers, Although the drying can be carried out using an infrared drying device, a far-infrared drying device, a microwave drying device, etc., a hot air drying device is preferably used. Note that if heat drying is performed under reduced pressure, the deaeration effect will be further improved. 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; if the heating temperature is high and there are few unreacted monomers, it will take a long time. good. Generally, it is preferable to heat and degas for 10 minutes to 10 hours so that the amount of unreacted monomer is 0.1 mol % or less. Next, in the present invention, an ethylene polymer is mixed with the modified polypropylene produced as described above. The ethylene polymer used in the present invention is, for example, an ethylene homopolymer polymerized by a high-pressure method or a medium-low pressure method, and ethylene and 60% by weight or less, preferably 40% by weight or less of other polymerizable monomers. Copolymers with ethylene and propylene, butene-1,3-methyl-butene-1, hexene-
One or two α-olefins such as 1,3-methyl-pentene-1,4-methyl-pentene-1
copolymers of ethylene and vinyl esters such as vinyl acetate and vinyl propionate, or saponified products thereof; ethylene and unsaturated carboxylic acids such as acrylic acid, methacrylic acid, and maleic acid, or derivatives thereof; For example, copolymers of anhydrides, esters, amides, imides, chlorides, metal salts, etc., polymers of ethylene and conjugated or non-conjugated dienes such as butadiene, dicyclopentadiene, ethylidenenorbornene, etc., or mixtures of the above polymers. say. These polymers may be subjected to various modifications such as oxidation, chlorination, chlorosulfonation, or grafting with an epoxy compound or a carboxyl group-containing compound. Among these, low density polyethylene, ethylene-propylene copolymer, and ethylene-butene-1 copolymer are preferably used. Ethylene polymer is MFI
(ASTM-D-1238, 230°C) is preferably in the range of 0.1 to 50 g/10 minutes. The amount of the ethylene polymer in the modified polypropylene composition is 5 to 50 parts by weight per 95 to 50 parts by weight of the modified polypropylene, preferably 10 to 40 parts by weight per 90 to 60 parts by weight of the modified polypropylene. When the amount of the ethylene polymer is less than 5 parts by weight, the effect of improving adhesion is small, and
If it exceeds 50 parts by weight, it is not preferable because not only the adhesiveness but also the mechanical strength is lowered. Further, it is also possible to mix unmodified polypropylene in addition to modified polypropylene and ethylene polymer, and unmodified polypropylene in addition to ethylene polymer. The proportion of unmodified polypropylene added is 0 to 95 parts by weight per 100 to 5 parts by weight of modified polypropylene.
Preferably, the amount is 10 to 90 parts by weight per 90 to 10 parts by weight of modified polypropylene. Mixing of modified polypropylene, ethylene polymer, or unmodified polypropylene as necessary can be performed using a tumbler, Henschel mixer, etc., and the mixture can be mixed using, for example, a screw extruder, Banbury mixer, mixing roll, etc. Melt and knead using Next, the modified polypropylene composition obtained as described above is heat-treated again. The heat treatment method and conditions are the same as those for the modified polypropylene in the first stage, and it is desirable that the heat treatment be performed so that the amount of unreacted monomer in the modified polypropylene composition is 0.05 mol% or less. However, in order to improve the adhesion of the resulting modified polypropylene composition, it is also preferable to perform a heat treatment beyond removing the unreacted monomers. The modified polypropylene composition of the present invention obtained by such two-stage heat treatment has significantly improved adhesive properties. 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, a modified polypropylene composition with good adhesiveness that does not cause foaming during molding is provided. 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 polypropylene composition. It is possible to provide a laminate with good adhesion of polypropylene and the like. 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. ●Measured using MFI ASTM D 1238-52T at 230°C with a load of 2160g. ●Amount of maleic anhydride A film with a thickness of approximately 0.1 mm was formed using heat press, and the infrared absorption spectrum was measured.
The amount of maleic anhydride was determined from the absorption peak intensity of maleic anhydride in ^-1 using the calibration curve shown in Fig. 2 of Koubunshi Kagaku Vol. 25, No. 274 (1968), p. 109.
The amount of maleic anhydride in the graft reaction is approximately 0.1 in thickness.
After a 6-hour acetone extraction of a 50 mm film,
The amount of maleic anhydride was taken as the amount of maleic anhydride in the sample dried under vacuum for 24 hours at a temperature of ℃. 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. ●Adhesive strength For adhesion between saponified ethylene-vinyl acetate copolymer, nylon, and polyethylene 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. ●Tensile modulus A 40mm extruder with L/D=20 is equipped with a T-die, and a sheet with a thickness of 0.5mm is extruded at 200℃.The obtained sheet is cut into strips with a width of 1cm in the MD direction, and the The distance between chucks is 5 depending on the testing machine.
cm, tensile test was performed at a tensile speed of 20 mm/min.
The tensile modulus was calculated from the initial slope. Examples 1 to 6 and Comparative Examples 1 to 3 MFI = 0.6 g/10 min, 100 parts by weight of propylene-ethylene random copolymer with ethylene content of 2.0% by weight, 2 parts by weight of maleic anhydride, 2,5-dimethyl-2 ,5-di(t-butyl-oxy)hexane
0.3 parts by weight, 0.1 parts by weight of butylated hydroxytoluene (BHT), 0.1 parts by weight of calcium stearate
Mix the weight parts in a Henschel mixer for 5 minutes,
Melt-kneading pelletization was performed at 220°C using a 40 mm extruder with L/D = 24, MFI = 75.3 g/10 minutes, total maleic anhydride amount 0.920 mol%, graft amount reacted maleic anhydride 0.485 mol%, unreacted maleic anhydride. Modified polypropylene (hereinafter also abbreviated as modified PP) with an acid content of 0.435 mol% was obtained. Next, heat treatment was performed at 145° C. for 4 hours using a constant temperature dryer (hereinafter also referred to as first-stage heat treatment) to obtain heat-treated modified polypropylene. This heat-treated modified polypropylene
MFI=52.7g/10min, total maleic anhydride amount 0.527
Mol%, graft reaction maleic anhydride amount is 0.475
The amount of unreacted maleic anhydride was 0.052 mol%. Furthermore, 15 parts by weight of the first stage heat-treated modified PP,
Unmodified homopolypropylene, ethylene content 80% by weight, MFI = 4.0g/10min at the proportions shown in Table 1;
After mixing ethylene-butene-1 random copolymer with MFI = 6.4 g/10 min and performing melt-kneading pelletization at 220°C using a 40 mm extruder with L/D = 24,
Heat treatment at 145℃ for 4 hours using a constant temperature dryer (hereinafter referred to as
A modified polypropylene composition was obtained. MFI of the obtained modified polypropylene composition,
Table 1 shows the maleic anhydride content, adhesive strength with saponified ethylene-vinyl acetate copolymer (hereinafter also referred to as silicified 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 210°C from a 40 mm extruder with L/D = 20, and a saponified ethylene-vinyl acetate copolymer (MFI = 5.4 g/10 min, ethylene content 25
mol%, degree of saponification 99% or more) at 30mm with L/D=24
The thickness of the modified polypropylene composition was extruded from an extruder at 210 °C through a coextrusion T-die, respectively.
A coextruded sheet with a thickness of 0.2 mm and a thickness of 0.1 mm of the saponified ethylene-vinyl acetate copolymer was formed, and the 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 4 In Example 3, the first stage heat treatment was performed for 8 hours,
The same procedure as in Example 3 was conducted except that the second heat treatment was not performed. The MFI of the obtained modified polypropylene composition was 6.4 g/10 min, the total amount of maleic anhydride was 0.076 mol%, the amount of graft-reacted maleic anhydride was 0.060 mol%, the amount of unreacted maleic anhydride was 0.016 mol%, and the amount of unreacted maleic anhydride was 0.016 mol%. Adhesive strength with chemical EVA is 300g/
It was 2cm warm. Comparative Example 5 The same procedure as in Example 3 was conducted except that the first heat treatment was not performed and the second heat treatment was performed for 8 hours. The MFI of the obtained modified polypropylene composition was 6.7 g/10 min, the total amount of maleic anhydride was 0.074 mol%, the amount of graft-reacted maleic anhydride was 0.059 mol%, the amount of unreacted maleic anhydride was 0.015 mol%, and the amount of unreacted maleic anhydride was 0.015 mol%. Adhesive strength with chemical EVA is 800g/
It was hot in 10 minutes. Comparative Example 6 The same procedure as in Example 3 was conducted except that neither the first heat treatment nor the second heat treatment was performed. The obtained modified polypropylene composition
MFI=7.5g/10min, total maleic anhydride amount is 0.135
Mol%, graft reaction maleic anhydride amount is 0.068
mol%, unreacted maleic anhydride amount is 0.067 mol%
The adhesive strength with saponified EVA was 0.
Also, foaming occurred during molding. Example 7 MFI=0.5g/10min 100 parts by weight of homopolypropylene, 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 were mixed in a Henschel mixer for 5 minutes. The mixture was mixed and melt-kneaded and pelletized at 250° C. using a 40 mm extruder with L/D=24.
MFI of the obtained modified polypropylene = 7.5g/10
The total amount of maleic anhydride was 0.203 mol%, the amount of graft-reacted maleic anhydride was 0.079 mol%, and the amount of unreacted maleic anhydride was 0.124 mol%. This modified polypropylene is dried using a constant temperature hot air dryer.
Heat treatment was performed at 155° C. for 3 hours (hereinafter also referred to as first stage heat treatment). MFI of the obtained heat-treated modified polypropylene = 6.4 g/10 min, total maleic anhydride amount is 0.108 mol%, graft reaction maleic anhydride amount is 0.074 mol%, unreacted maleic anhydride amount is 0.034
It was mol%. Next, 80 parts by weight of this heat-treated modified polypropylene had an ethylene content of 70% by weight,
Mix 20 parts by weight of ethylene-propylene random copolymer with MFI = 5.3 g/10 min, L/D = 24 40
Melt-kneading pelletization was performed at 220° C. using a mm extruder, and heat treatment was performed at 155° C. for 3 hours using a constant temperature dryer (hereinafter also referred to as second-stage heat treatment) to obtain a modified polypropylene composition. The MFI of the obtained modified polypropylene composition was 6.1 g/10 min, the total amount of maleic anhydride was 0.080 mol%, the amount of graft-reacted maleic anhydride was 0.058 mol%, and the amount of unreacted maleic anhydride was 0.022 mol%. . This modified polypropylene composition was passed through a 40 mm extruder with L/D=20.
At 210℃, 30mm of nylon 6 with L/D=24
They were each coextruded from an extruder at 250°C through a coextrusion T-die to form a coextruded sheet with a modified polypropylene composition layer of 0.2 mm thickness and a nylon 6 layer of 0.1 mm thickness. The adhesive strength was 4100g/2cm. Comparative Example 7 The same procedure as in Example 7 was conducted except that the first heat treatment was performed for 6 hours and the second heat treatment was not performed. The MFI of the obtained modified polypropylene composition was 6.0 g/10 min, and the total amount of maleic anhydride was
0.079 mol%, the amount of maleic anhydride in the graft reaction is
The amount of unreacted maleic anhydride is 0.023 mol%, and the adhesive strength with nylon 6 is 2300 g/
It was 2cm warm. Comparative Example 8 The same procedure as in Example 7 was conducted except that the first heat treatment was not performed and the second heat treatment was performed for 6 hours. MFI of the obtained modified polypropylene composition = 6.3 g/10 min, total amount of maleic anhydride
0.082 mol%, graft reaction maleic anhydride amount
The amount of unreacted maleic anhydride is 0.022 mol%, and the adhesive strength with nylon 6 is 2700 g/2.
It was cm. Comparative Example 9 The same procedure as in Example 7 was conducted except that neither the first heat treatment nor the second heat treatment was performed. MFI of the obtained modified polypropylene = 7.5
g/10 min, total maleic anhydride amount is 0.152 mol%,
The amount of maleic anhydride in the graft reaction is 0.062 mol%,
The amount of unreacted maleic anhydride is 0.090 mol%,
The adhesive strength with nylon 6 was 0. Also, foaming occurred during molding. Comparative example 10 MFI=0.5g/10min homopolypropylene 80 parts by weight, ethylene content 70% by weight, MFI=5.3g/10
20 parts by weight of ethylene-propylene random copolymer, 0.3 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 were mixed in a Henschel mixer for 5 minutes, Melt kneading pelletization was performed using a 40 mm extruder with /D=24, and MFI=4.5g/10
A modified polypropylene composition was obtained in which the total amount of maleic anhydride was 0.175 mol %, the amount of graft-reacted maleic anhydride was 0.120 mol %, and the amount of unreacted maleic anhydride was 0.055 mol %. Next, this modified polypropylene composition was heated and degassed at 155°C for 3 hours using a constant-temperature air dryer, so that MFI = 4.3 g/10 minutes, total maleic anhydride amount 0.135 mol%, and graft reaction maleic anhydride amount. 0.117 mol%, amount of unreacted maleic anhydride
A 0.018 mol % modified polypropylene composition was obtained.
The adhesive strength between this modified polypropylene composition and nylon 6 was 1100 g/2 cm. Example 8 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 mm 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 dried at 150°C using a constant temperature hot air dryer.
Heat-treated for 4 hours (hereinafter also referred to as first-stage heat treatment) at
0.110 mol%, graft reaction maleic anhydride amount
A modified polypropylene containing 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 specific gravity of 0.920,
Mix 20 parts by weight of low density polyethylene with MFI=2.7g/10min and use a 40mm extruder with L/D=24.
Melt-kneading pelletization was performed at 220°C, followed by heat treatment at 150°C for 4 hours using a constant temperature dryer (hereinafter also referred to as second-stage heat treatment) to obtain a modified polypropylene composition. The MFI of the obtained modified polypropylene composition was 11.7 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 0.017 mol%. This modified polypropylene composition was extruded through a coextrusion T-die at 210°C from a 40 mm extruder with L/D = 20, and polyethylene phthalate was extruded through a coextrusion T-die from a 30 mm extruder with L/D = 24 at 270°C. layer thickness 0.2
mm, thickness of polyethylene terephthalate layer 0.1mm
When a coextruded sheet was made and the adhesive strength was measured, it was 500 g/2 cm. Comparative Example 11 The same procedure as in Example 8 was conducted except that the first heat treatment was performed for 8 hours and the second heat treatment was not performed. The MFI of the obtained modified polypropylene composition was 12.0 g/10 min, and the total amount of maleic anhydride was
0.084 mol%, the amount of maleic anhydride in the graft reaction is
The amount of unreacted maleic anhydride was 0.016 mol%, and the adhesive strength with polyethylene terephthalate was 200 g/2 cm. Comparative Example 12 The same procedure as in Example 8 was conducted except that the first heat treatment was not performed and the second heat treatment was performed for 8 hours. The MFI of the obtained modified polypropylene composition was 11.5 g/10 min, the total amount of maleic anhydride was 0.088 mol%, the amount of graft-reacted maleic anhydride was 0.070 mol%, and the amount of unreacted maleic anhydride was 0.018.
% by mole, and the adhesive strength with polyethylene terephthalate was 300 g/10 minutes. Comparative Example 13 The same procedure as in Example 8 was conducted except that neither the first heat treatment nor the second heat treatment was performed. The obtained modified polypropylene composition
MFI=20.1g/10min, total amount of maleic anhydride is
0.182 mol%, the amount of maleic anhydride in the graft reaction is
The amount of unreacted maleic anhydride was 0.072 mol%, and the adhesive strength with polyethylene terephthalate was 0. Also, foaming occurred during molding. Comparative Example 14 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, and melt-kneaded and pelletized at 190°C using a 40 mm 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 treated at 150℃ for 4 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 50
g/2cm. Comparative Example 15 The modified polypropylene obtained in Examples 1 to 6 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. MFI of this modified polypropylene (A) = 56.7 g/10 minutes,
The total amount of maleic anhydride was 0.571 mol%, the amount of graft-reacted maleic anhydride was 0.480 mol%, and the amount of unreacted maleic anhydride was 0.091 mol%. next,
Modified polypropylene (A) 15 parts by weight, MFI = 4.0g/
65 parts by weight of unmodified homopolypropylene for 10 minutes, ethylene content 80% by weight, MFI = 6.4 g/20 parts by weight of ethylene-butene-1 random copolymer for 10 minutes,
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 mm extruder with L/D = 24, MFI = 6.3 g/10 minutes, total maleic anhydride amount 0.085 mol%, graft reaction maleic anhydride amount 0.070 mol%, unreacted maleic anhydride amount 0.015
A modified polypropylene composition of mol % was obtained. It was determined in the same manner as in Example 3. This composition and saponification
The adhesive strength with EVA was 50 g/2 cm. Comparative Example 16 The modified polypropylene (A) obtained in Comparative Example 15 was extracted with acetone for 8 hours using a Soxhlet extractor, and the
Modified polypropylene (B) was dried under reduced pressure for 24 hours at °C to obtain a modified polypropylene (B) with MFI = 51.6 g/10 min, total maleic anhydride amount of 0.500 mol%, graft reaction maleic anhydride amount of 0.463 mol%, and unreacted maleic anhydride amount of 0.037 mol%. I got it. Next, 15 parts by weight of modified polypropylene (B),
MFI = 65 parts by weight of homopolypropylene for 4.0 g/10 min, ethylene content 80% by weight, MFI = 20 parts by weight of ethylene-butene-1 random copolymer for 6.4 g/10 min, 0.05 part by weight of maleic anhydride, BHT0. 1 part by weight and 0.1 part by weight of calcium stearate were mixed in a Henschel mixer for 5 minutes, and 40
Pelletize at 220℃ using mm extruder,
A modified polypropylene composition having an MFI of 6.7 g/10 minutes, a total amount of maleic anhydride of 0.083 mol%, an amount of graft-reacted maleic anhydride of 0.069 mol%, and an amount of unreacted maleic anhydride of 0.014 mol% was obtained. The adhesive strength between this composition and saponified EVA, determined in the same manner as in Example 3, was 0. Comparative Example 17 The same procedure as Comparative Example 16 was carried out except that maleic anhydride was not added. MFI of the obtained modified polypropylene composition = 6.4 g/10 minutes,
The total amount of maleic anhydride was 0.080 mol%, the amount of graft-reacted maleic anhydride was 0.075 mol%, and the amount of unreacted maleic anhydride was 0.005 mol%, which were determined in the same manner as in Example 2. The adhesive strength between this composition and saponified EVA was 200 g/2 cm. Table 2 below shows Example 3 and Comparative Examples 4, 5, 15, 16.
and 17 results are also shown.

【table】

【table】

Claims (1)

[Scope of Claims] 1. Modified polypropylene obtained by melt-kneading a mixture of polypropylene, unsaturated carboxylic acids, and organic peroxides is heat-treated at a temperature of 60°C or higher, and then 95 to 50% by weight of the modified polypropylene is heated at a temperature of 60°C or higher. 1. A method for producing a modified polypropylene composition, which comprises mixing 5 to 50 parts by weight of an ethylene polymer, melt-kneading the mixture, and then heat-treating the mixture 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. The method according to claim 1, wherein the ethylene polymer is at least one selected from ethylene-butene-1 copolymer, ethylene-propylene copolymer, and low-density polyethylene. 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 of 5 parts by weight and 0.01 to 1 part by weight of an organic peroxide using a screw extruder.