JPH1149866A - Crosslinked soft polyolefin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject polyolefin excellent in heat resistance, low shrinkage, transparency, and resistance to whitening when flexed or oriented, and useful for e.g. medical equipment, food packaging materials, by irradiating a flexible polyolefin containing a specific flexibilizing component with rays. SOLUTION: A flexible polyolefin (e.g. a block copolymer composed of 1-70 wt.% of a polypropylene component and 90-30 wt.% of a propylene-ethylene random copolymer composed of 10 mol.% of ethylene monomer unit and 90-40 mol.% of propylene monomer unit) with the component eluted at -40 to 30 deg.C accounting for 10-90 wt.% of the total eluted components fractionated by temperature rising elution fractionation technique in the elution curve with the abscissa as temperature ( deg.C) and the ordinate as integrated weight proportion (wt.%) is irradiated with electron beams or rays so as to be pref. 1-75 wt.% in gel fraction, thus obtaining the objective crosslinked flexible polyolefin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a crosslinked soft polyolefin obtained by irradiating a soft polyolefin with an electron beam and / or radiation and having excellent heat resistance, low shrinkage, transparency, and whitening resistance during bending and stretching. Related to polyolefin.

[0002]

2. Description of the Related Art Hitherto, polyolefin resins have the advantage of excellent mechanical properties and have been used for various applications.
However, in order to further improve the mechanical properties, studies have been made on various types of chemical crosslinking with a polyfunctional monomer or the like, and on crosslinking by irradiating a polyolefin with radiation.

However, the above-mentioned chemical crosslinking involves complicated workability in the kneading step and the like, and there is a possibility that unreacted crosslinking agents and crosslinking aids affect the environment and the properties of the resin itself. is there. Furthermore, the mechanical properties, appearance, and transparency of the soft resin are greatly impaired due to the increase in the dielectric constant and the occurrence of leakage current in the electrical properties, and the poor compatibility between the monomer compositions. This was not preferable because of the fear.

[0004] On the other hand, crosslinked polyolefins obtained by irradiating polyolefins with radiation are generally well known. When a polyolefin is irradiated, the crosslinking effect is low and the molecular weight is reduced at a small dose.At a large dose, both the crosslinking of the polymer and the degradation of the molecular weight due to the decomposition of the polymer are greatly expressed, and the obtained resin is a mechanical resin. It was not preferable in physical properties.

In order to prevent the deterioration of the resin due to the above-mentioned irradiation, JP-A-54-125240 discloses a method of irradiating a polyolefin such as polypropylene or polyethylene containing a large amount of an antioxidant with a radiation. Has been proposed.

[0006]

However, conventionally,
Few examples have been reported on the behavior of radiation crosslinking for flexible polyolefins.

[0007] From the above background, an object of the present invention is to provide a compound which cannot be obtained with a conventional crosslinked polyolefin.

[0008]

Means for Solving the Problems The present inventors have intensively studied radiation or electron beam crosslinking of soft polyolefin. As a result, when the soft polyolefin having the specific soft component is irradiated with radiation, the influence of the irradiation atmosphere is low, the deterioration of the resin occurring during irradiation and the deterioration with time after irradiation are extremely suppressed, and the heat resistance and low shrinkage It has been found that a crosslinked soft polyolefin having improved transparency, whitening resistance at the time of bending and stretching and the like can be obtained, and the present invention has been completed.

That is, according to the present invention, the elution components separated by the elevated temperature elution fractionation method are represented by a temperature (° C.) on the horizontal axis and a cumulative weight ratio (% by weight (wt%)) on the vertical axis. , Eluting components at −40 ° C. to 30 ° C. are 10 wt% to 9%
It is a crosslinked soft polyolefin obtained by cross-linking 0 wt% of a soft polyolefin with an electron beam and / or radiation.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, regarding the elution components separated by a temperature rising elution fractionation method, in the elution curve, the horizontal axis represents temperature (° C.) and the vertical axis represents integrated weight ratio (wt%). The measurement of the eluted component at 40 ° C. to 30 ° C. can be performed by a known method without any limitation. In general, the temperature eluted fractionation method is a means for analyzing the composition or stereoregularity or amorphous distribution of a crystalline polymer such as polyolefin, and is performed by the following operation. First, a high-temperature polymer solution is introduced into a column filled with a filler such as diatomaceous earth or glass beads, and the temperature of the column is gradually lowered to crystallize the filler surface in order from the component having the higher melting point. Next, by gradually increasing the column temperature, components are eluted and collected in order from the component having the lowest melting point. In the present invention, the cooling rate of the column temperature was 2 ° C./hour.
The rate of increase in the column temperature was 4 ° C./hour.

Further, o-dibromobenzene was used as a solvent. For specific operation methods, for example,
Journal of Applied Polymer
Science; Applied Polywer
Symposium 45, 1-24 (1990). In the fractionation of the copolymer composition by the present fractionation method, the amorphous or extremely low-crystalline resin composition is fractionated at a relatively low temperature range of room temperature or lower, and the components having high crystallinity are increased as the elution temperature increases. It will be separated. The amount of each fractionated component can be calculated from an elution curve in which the horizontal axis indicates the elution temperature and the vertical axis indicates the integrated weight ratio.

In the present invention, a soft polyolefin containing less than 10% by weight of an eluting component at -40 ° C. to 30 ° C. contains a large amount of a crystalline component, so that the flexibility is not good and the crosslinking effect of the resin is low. Further, the irradiation atmosphere during irradiation has a large influence such as deterioration due to main chain cutting. The deterioration of the resin during irradiation and the deterioration with time after irradiation are extremely large, and the effectiveness of the present invention cannot be exhibited.

Further, in the present invention, -40 ° C. to 30 ° C.
In the case of a soft polyolefin having an elution component of more than 90% by weight, adhesiveness is high and blocking occurs, which is not preferable.

Specific examples of the soft polyolefin having the above-mentioned properties include a homopolymer of propylene and a copolymer of propylene and another α-olefin. Here, the α-olefin other than propylene means ethylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 3-methyl-1-butene, 4-
Methyl-1-pentene and the like. The copolymer of propylene and another α-olefin may be any combination of propylene and one or more α-olefins. Further, copolymers of propylene and vinyl acetate, acrylic acid esters, unsaturated silane compounds, unsaturated carboxylic acids, and the like are also included.

The polypropylene which can be suitably used in the present invention includes a propylene-ethylene random copolymer and a propylene-ethylene-butene copolymer.

The propylene-ethylene random copolymer composition contains 20 to 9 monomer units based on propylene.
It is preferable to use a copolymer of 0 mol% and a monomer unit based on ethylene of 80 to 10 mol% in combination with the low-temperature eluting component in order to prevent deterioration of the resin at the time of crosslinking due to radiation or the like. . In consideration of the flexibility of the obtained propylene-ethylene-butene copolymer, the monomer unit based on propylene is 20 to 90 mol%, the monomer unit based on ethylene is 75 to 5 mol%, and 1- The copolymer is preferably a copolymer of 75 to 5 mol% of a monomer unit based on butene.

When the ethylene content of the propylene-ethylene random copolymer is less than 10 mol%, sufficient softness is not exhibited, and the effect of preventing deterioration at the time of crosslinking by radiation or the like is poor. %, The obtained copolymer has poor tackiness in the particle properties and tends to fail to obtain good fluidity in the production process. In addition, propylene is a propylene-ethylene-butene copolymer with 8
When the content exceeds 0 mol%, sufficient softness is not exhibited, and the effect of preventing deterioration at the time of crosslinking by radiation or the like is poor.
If it is less than 0 mol%, the heat resistance tends to decrease.
Propylene-ethylene-butene copolymer with 5 ethylene
When the amount is less than mol%, sufficient softness is not exhibited, and the effect of preventing deterioration at the time of crosslinking by radiation or the like is poor.
If it exceeds 5 mol%, the resulting copolymer has high tackiness in the particle properties, and good fluidity tends not to be obtained in the production process. When 1-butene is less than 5 mol% in the propylene-ethylene-butene copolymer, sufficient softness is not exhibited, and when it exceeds 75 mol%, the obtained copolymer has high tackiness in particle properties and is excellent. Tend not to obtain high fluidity.

In consideration of flexibility in the present invention, the soft polyolefin resin which can be more preferably used may be a block copolymer containing a copolymer of propylene and another α-olefin. Here, the α-olefin other than propylene means ethylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene,
3-methyl-1-butene, 4-methyl-1-pentene and the like. In the copolymer of propylene and another α-olefin, the α-olefin may be in one or more combinations. In addition, copolymers of propylene and vinyl acetate, acrylic acid ester, unsaturated silane compound, unsaturated carboxylic acid, etc. may also be mentioned. Copolymers of propylene and any combination of at least one kind may be used, or may be used by mixing. Is also good. In the present invention,
As a block copolymer suitably used, a block copolymer including a propylene-ethylene random copolymer is preferably exemplified. Considering the softness of the obtained block copolymer, 1 to 70% by weight of the polypropylene component,
Propylene-ethylene random copolymer component 99-30 containing 10-60 mol% of monomer units based on ethylene and 90-40 mol% of monomer units based on propylene
It is preferable to use a block copolymer composed of% by weight. That is, when the content is less than 1% by weight, the viscosity of the particle properties of the block copolymer is high, and the fluidity tends to decrease. If the content of the polypropylene component exceeds 70% by weight, sufficient flexibility and whitening resistance may not be obtained.

The soft polyolefin used in the present invention has a horizontal axis representing temperature (° C.) and a vertical axis representing cumulative weight ratio (wt%) of the eluted components separated by the temperature-elution separation method.
If the elution component at -40 to 30 ° C. in the elution curve represented by is 10 wt% to 90 wt%, other polyolefins, for example, polypropylene, propylene-ethylene random copolymer, propylene-ethylene block copolymer, High-density polyethylene, medium-density polyethylene, low-density polyethylene, linear polyethylene obtained by copolymerizing ethylene and C4 to C10, ethylene-propylene copolymer (EPDM), ethylene-butene-1 copolymer, propylene-butene- Polyolefin such as 1 copolymer, poly 1-butene, poly 1-pentene, poly 4-methylpentene-1, polybutadiene and polyisoprene may be blended.

Further, other resins such as ethylene-vinyl acetate copolymer, ethylene methacrylate, polychloroprene, halogenated polyethylene, halogenated polyethylene and the like may be used as long as the physical properties of the soft polyolefin used in the present invention are not impaired. Polypropylene, fluororesin, acrylonitrile-butadiene rubber, polystyrene, polybutadiene terephthalate, polycarbonate, polyvinyl chloride, fluororubber, polyethylene terephthalate,
Petroleum resin-based hydrocarbons such as polyamide, acrylonitrile-butadiene-styrene copolymer, petroleum resin, hydrogenated petroleum resin, terpene resin, hydrogenated terpene resin, and styrene-
Such as butadiene-styrene block copolymer, styrene-isoprene-styrene block copolymer, styrene-ethylene-butylene-styrene block copolymer, styrene-propylene-butylene-styrene block copolymer and hydrogenated styrene-butadiene rubber. An aromatic vinyl rubber may be compounded. These other polyolefin resins and other resins are the soft polyolefin resin 10 of the present invention.
It is preferable to mix 1 to 40 parts by weight with respect to 0 parts by weight.

The soft polyolefin resin in the present invention may be obtained by any method.
For example, the following polymerization method is used. The catalyst is
Metallocene catalysts consisting of metallocene compounds using transition metals of Group IV of the periodic table and methylaluminoxane or alkylaluminum or alkylaluminum halide, vanadium catalysts, titanium trichloride or titanium tetrachloride supported on magnesium compounds such as magnesium chloride Examples thereof include a titanium-based catalyst, an anionic polymerization catalyst, and a radical polymerization catalyst, which may be used alone or in combination. In general, Ziegler
A natter type stereospecific catalyst, a titanium-containing catalyst supported on magnesium chloride or a titanium trichloride-based stereospecific catalyst, and a cocatalyst such as triethylaluminum or diethylaluminum are added to propylene or a mixture thereof with another α-olefin. Those obtained by polymerization are preferred.
The polymerization may be carried out in a gas phase or in a liquid phase. Further, it may be polymerized in an inert liquid or an inert solvent for the catalyst. In addition,
Such polymerization may be produced by multistage polymerization in addition to batch polymerization. In such a multi-stage polymerization,
It may be one produced solely in the gas phase or solely in the liquid phase, or one produced by combining the liquid phase polymerization step and the gas phase polymerization step. During the polymerization, one obtained by controlling the molecular weight by introducing hydrogen or one obtained by degrading the obtained polymer with a molecular weight regulator such as an organic peroxide may be used.

In the present invention, the fluidity of the soft polyolefin at the time of melting is not particularly limited, and the melt flow rate (hereinafter abbreviated as MFR) is 0.1 to 100 g / 10 min in consideration of moldability. It is preferably in the range, and more preferably in the range of 0.5 to 60 g / 10 min. Here, the melt flow rate is a value measured according to JIS K7210.

In the present invention, the irradiation of the electron beam and / or radiation can be performed by a known irradiation method without any limitation. Taking into account the characteristics of the resin obtained, a dose of 10
５００500 kGy is preferred, and more preferably 30-500 kGy.
400 kGy is preferred. If it is less than 10 kGy, sufficient whitening resistance cannot be obtained, and if it exceeds 500 kGy, the resin is significantly deteriorated, and the resin is yellowed, which is not a favorable tendency.

In the present invention, the obtained crosslinked soft polyolefin which has been crosslinked by irradiation with an electron beam and / or radiation has a gel fraction in consideration of the characteristics of the obtained resin.
It is preferably 1 to 75% by weight, more preferably 20% by weight.
~ 60% by weight is preferred. If it is less than 1% by weight, sufficient whitening resistance cannot be obtained, and if it exceeds 75% by weight, the resin is significantly deteriorated, and the resin is yellowed, which is not a favorable tendency.

In the present invention, the irradiation with the electron beam and / or radiation may be performed before or after forming the crosslinked soft polyolefin.
There is no particular limitation. In the present invention, the mixing of other resins is not particularly limited, and a soft polyolefin may be mixed before irradiation, or a soft polyolefin may be mixed after irradiation.

In the crosslinked soft polyolefin of the present invention, a known phenolic antioxidant can be used without any limitation, if necessary. Specifically, 2,6-di-tert-butyl-4-hydroxyphenol, 2,6-di-tert-butyl-p-cresol, 2,6-diphenyl-4-octadecyloxyphenol, stearyl (3,5 -Di-tert-butyl-4-hydroxyphenyl) propionate, distearyl (3,5-di-tert-butyl-4-hydroxybenzyl) phosphonate, thiodiethylene glycol bis [(3,5-di-tert-butyl-4-hydroxyphenyl) ) Propionate], 4,4′-thiobis (6-tert-butyl-m-cresol), 2-octylthio-4,6
-Di (3,5-di-tert-butyl-4-hydroxyphenoxy) -s-triazine, 2,2'-methylenebis (4-
Methyl-6-tert-butylphenol), 2,2′-methylenebis (4-ethyl-6-tert-butylphenol),
Bis [3,3'-bis (4-hydroxy-3-tert-butylphenyl) butyric acid] glycol ester, 4,4'-butylidenebis (6-tert-butyl-m-
Cresol), 2,2'-ethylidenebis (4,6-di-tert-butylphenol), 2,2'-ethylidenebis (4-tert-butyl-6-tert-butylphenol), 1,
1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, bis [2-tert-butyl-4
-Methyl-6- (2-hydroxy-3-tert-butyl-5
-Methylbenzyl) phenyl] terephthalate, 1,
3,5-tris (2,6-dimethyl-3-hydroxy-
4-tert-butylbenzyl) isocyanate, 1,3,5
-Tris (3,5-di-tert-butyl-4-hydroxybenzyl) isocyanate, 1,3,5-tris (3,5-
Di-tert-butyl-4-hydroxybenzyl) -2,4,6
-Trimethylbenzene, 1,3,5-tris [(3,5
-Di-tert-butyl-4-hydroxyphenyl) propionyloxyethyl] isocyanate, tetrakis [methylene (3,5-di-tert-butyl-4-hydroxyphenyl)
Propionate] methane, 2-tert-butyl-4-methyl-6- (2-acryloyloxy-3-tert-butyl-5
-Methylbenzyl) phenol, 3,9-bis (1,1
-Dimethyl-2-hydroxyethyl) -2,4,8,1
0-tetraoxaspiro [5,5] undecane-bis [β- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionate], triethylene glycol bis [β- (3-tert-butyl-4) -Hydroxy-5-methylphenyl) propionate].

These phenolic antioxidants are used in an amount of 0.001 to 1 part by weight, preferably 0.01 to 0.8 part by weight, per 100 parts by weight of the soft polyolefin. The above phenolic antioxidants may be used alone or in combination of two or more. If the amount is less than 0.001 part by weight, the resin is significantly deteriorated, and the resin yellows, which is not preferable. If the amount exceeds 1 part by weight, blooming of the antioxidant is remarkable, and the appearance of the molded product is deteriorated, which is not preferable.

Further, the soft polyolefin of the present invention includes:
If necessary, known organic phosphorus antioxidants can be used without any limitation. Specifically, trisnonylphenyl phosphite, tris (2,4-di-tert-butylphenyl) phosphite, di (tridecyl) pentaerythritol diphosphite, bis (2,4-di-tert-butylphenyl) pentaes Litol diphosphite, bis (2,6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphite, tetra (tridecyl)
Isopropylidene diphenol diphosphite, tetra (tridecyl) -4,4-n-butylidenebis (2-tert-butyl-5-methylphenol) diphosphite, hexa (tridecyl) -1,1 ', 3-tris (3- Tert-butyl-4-hydroxy-5-methylphenyl) butanetriphosphite, 2,2'-methylenebis (4,6-
Di-tert-butylphenyl) octyl phosphite, 2,
2'-methylenebis (4,6-di-tert-butylphenyl)
Octadecyl phosphite, 2,2'-methylenebis (4,6-di-tert-butylphenyl) fluorophosphite, tetrakis (2,4-di-tert-butylphenyl) biphenylenediphosphonite and the like can be mentioned. These organophosphorus antioxidants are used in an amount of 0.001 to 1 part by weight, preferably 0.01 to 0.8 part by weight, based on the soft polyolefin.
It is preferable to mix by weight. One of the above organic phosphorus antioxidants may be used alone, or two or more thereof may be used in combination. If the amount is less than 0.001 part by weight, the resin is significantly deteriorated, and the resin yellows, which is not preferable.
If the amount exceeds 1 part by weight, blooming of the antioxidant is remarkable, and the appearance of the molded product is deteriorated, which is not preferable.

Further, as the soft polyolefin, known thioether-based antioxidants can be used without any limitation, if necessary. Specifically, β-alkylmercaptopropionic acid esters such as dialkylthiodipropionates such as dilauryl, dimyristyl and distearyl esters of thiodipropionic acid, and polyols such as pentaerythritol tetra (β-dodecylmercaptopropionate) are used. can give. These thioether-based antioxidants include soft polyolefin-100.
0.001-1 part by weight with respect to parts by weight, preferably,
It is preferable to mix 0.01 to 0.8 parts by weight. The above thioether-based antioxidants may be used alone or in combination of two or more. If the amount is less than 0.001 part by weight, the resin is significantly deteriorated, and the resin yellows, which is not preferable. If the amount exceeds 1 part by weight, blooming of the antioxidant is remarkable, and the appearance of the molded product is deteriorated, which is not preferable.

When the above-mentioned phenolic antioxidant, organic phosphorus antioxidant and thioether antioxidant are used in combination, 0.001 to 1 part by weight, preferably 100 to 1 part by weight of soft polyolefin, 0.01 ~
If it is 0.8 parts by weight, only one kind thereof may be used, or two or more kinds thereof may be used.

The above-mentioned soft polyolefin used in the present invention may further contain, if necessary, wollastonite, mica, bentonite, clay, zeolite,
Kaolin, perlite, diatom, asbestos, barium sulfate, calcium carbonate, silica, silicate, glass, metal hydroxide compound, aluminum hydroxide, magnesium hydroxide, zinc oxide, magnesium oxide, aluminum silicate, calcium silicate, carbon, natural An inorganic filler such as fiber or synthetic fiber may be blended. Here, the filler is
Two or more kinds may be used in combination. The amount of the inorganic filler is 0.1 to 100 parts by weight of the soft polyolefin.
Preferably, it is -80 parts by weight. Further, various additives may be appropriately added to the soft polyolefin as long as the effects of the invention are not impaired. Specifically, hindered amine-based heat stabilizers; hindered amine-based weathering agents; benzophenone-based, benzotriazole-based, benzoate-based ultraviolet absorbers; nonionic, cationic, anion-based antistatic agents; bisamides And wax dispersants; amide, wax, organometallic salt and ester lubricants; oxide and other decomposers; melamine, hydrazine, amine and other metal deactivators; Flame retardants such as organic, phosphoric, antimony trioxide, magnesium hydroxide, and red phosphorus; organic pigments; inorganic pigments; sorbitol-based, aromatic metal phosphate-based, and organic acid metal-based clarifying agents or compounds. Nucleating agent; anti-fogging agent;
Antiblocking agents; foaming agents; organic fillers; metal ion-based inorganic antibacterial agents, organic antibacterial agents, and the like.
It is not limited to these.

In the present invention, the above components can be blended by any ordinary method which is performed by mixing resins without any limitation. For example, after adding other resins, additives, fillers, etc. to the powdery or pellet-like (1) soft polyolefin and mixing with a tumbler, Henschel mixer, Banbury mixer, ribbon feeder, super mixer, etc. Alternatively, a kneading temperature of 150 ° C. to 350 ° C., preferably 190 ° C. to 28 ° C., using a multi-screw extruder (preferably a melt-kneading apparatus capable of degassing), a roll, or the like.
A method of melt-kneading at 0 ° C. to form pellets or the like is preferable.
The order of addition of each component is not particularly limited, and each component may be mixed in a different order from the above method. Furthermore, a masterbatch in which other additives and filler components are concentrated and blended at a high concentration can be prepared and mixed and used.

[0033]

The crosslinked flexible polyolefin of the present invention is
Excellent heat resistance, low shrinkage, transparency, and whitening resistance during bending and stretching. Therefore, the crosslinked flexible polyolefin of the present invention is a film, a sheet, a bottle, a case, a pipe,
Including various molded products such as fibers and industrial parts, medical equipment, stationery, surface protection materials, building material sheets, decorative sheets, inner surface protection materials, coating materials, sealants, water barrier materials, decorative skin materials, food packaging materials, etc. It can be used very effectively as a material for various waterproofing materials, electric parts, electric wire covering materials and electric wire-related members, and various molded articles requiring extremely little impact on the environment and sanitation. Examples of the above molded product film include a surface protection film, a vehicle protection film, a steel plate protection film, a dicing film, a decorative film, a wrap film, a shrink film, a stretch film, a pallet stretch film, a sealant film, a heat welding film, and heat. Adhesive film, adhesive film, adhesive bandage base film, label film, building material film, building material skin film, stationery film, adhesive base film, adhesive tape, binding tape, masking tape, display tape, packaging tape, Examples include electrical insulating tapes, marking films, agricultural films, house films, medical films, medical adhesive tapes, infusion bags, and surgical tapes.

[0034]

EXAMPLES The present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to these examples.

In the examples, various measurements and evaluations were made by the following methods.

(A) Gel fraction in resin A soft polyolefin obtained by electron beam irradiation and irradiation was weighed and subjected to Soxhlet extraction with p-xylene.
After the drying, the residue was dried for 48 hours, and the gel fraction was determined by the following equation.

Gel fraction [%] = extracted dry residue × 100
/ Weight before extraction (b) Heat resistance Measurement was performed according to JIS K7206.

(C) Shrinkage ratio Width 100 mm x length 100 mm x thickness 2 m by injection molding
m, and after annealing at 23 ° C. for 48 hours,
The dimensions of the flat plate were measured in the flow direction (MD) of the resin and the direction (TD) intersecting with the flow direction of the resin, and the shrinkage was determined by the following equation.

Shrinkage [%] = Plate size (dimension in MD or TD direction) × 100 / Original size of mold (d) Transparency Measurement was carried out according to JIS K7105. The thickness of the flat plate was set at 1 mmt.

(E) Whitening resistance A sheet having a length of 100 mm × width 100 mm × thickness 100 μm was prepared, and a folded portion was sandwiched between steel plates of length 60 mm × width 60 mm × thickness 5 mm, and a stress of 10 MPa was applied for 1 minute. The bent portion of the film was opened, and the whitening state was visually determined.

1. No whitening 2. 2. Thin white on the bending line 3. The bending line is whitened. 4. There is thin whitening in addition to the bending line. Sample 1 was whitened due to craze on the streaks other than the bending line. Sample 1 Polymerization was performed in the presence of δ-type titanium trichloride and diethylaluminum chloride to obtain a soft propylene ethylene block copolymer shown in Table 1.

Sample 2 Polymerization was carried out in the presence of δ-type titanium trichloride and diethylaluminum chloride to obtain a polypropylene homopolymer shown in Table 1.

Sample 3 Polymerization was carried out in the presence of a titanium tetrachloride compound supported on magnesium chloride and triethylaluminum to obtain a propylene ethylene copolymer shown in Table 1.

Sample 4 Polymerization was carried out in the presence of a magnesium chloride-supported titanium tetrachloride compound and triethylaluminum to obtain a soft propylene ethylene copolymer shown in Table 1.

Sample 5 Polymerization was carried out in the presence of δ-type titanium trichloride and diethylaluminum chloride to obtain a soft propylene ethylene block copolymer shown in Table 1.

Examples 1 to 8 The antioxidant tetrakis [methylene (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] methane was added in an amount of 0.05 part by weight based on 100 parts by weight of the soft polypropylene resin of the sample 1. Parts, and sufficiently stirred and mixed with a Henschel mixer. Thereafter, melt kneading was performed by an extruder, and a soft polyolefin was obtained by strand cutting. The obtained soft polyolefin was irradiated at the dose shown in Table 1. Table 1 shows the results obtained by shaping the soft polyolefin obtained by irradiation and using it for various measurements and evaluations.

Comparative Examples 1 and 2 The antioxidant tetrakis [methylene (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] methane was added to 100 parts by weight of the soft propylene ethylene block copolymer of Sample 1 described above. 0.05 parts by weight were mixed and sufficiently stirred and mixed by a Henschel mixer. Thereafter, melt kneading was performed by an extruder, and a soft polyolefin was obtained by strand cutting. The obtained soft polyolefin was irradiated at the dose shown in Table 1. Table 1 shows the results obtained by shaping the soft polyolefin obtained by irradiation and using it for various measurements and evaluations.

Comparative Examples 3 and 4 The antioxidant tetrakis [methylene (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] was added to 100 parts by weight of the polypropylene homopolymer of Sample 2 described above.
Methane was mixed in an amount of 0.05 part by weight, and sufficiently stirred and mixed by a Henschel mixer. Thereafter, melt kneading was performed by an extruder, and a polyolefin was obtained by strand cutting. The obtained polyolefin was irradiated at the dose shown in Table 1. Table 1 shows the results obtained by molding the resin composition obtained by irradiation and using it for various measurements and evaluations.

Comparative Examples 5 and 6 The antioxidant tetrakis [methylene (3,5) was added to 100 parts by weight of the above propylene ethylene random copolymer.
[Di-tert-butyl-4-hydroxyphenyl) propionate] methane was added in an amount of 0.05 part by weight, and sufficiently mixed with a Henschel mixer. Thereafter, melt kneading was performed by an extruder, and a polyolefin was obtained by strand cutting. The obtained polyolefin was irradiated at the dose shown in Table 1. Table 1 shows the results obtained by molding the resin composition obtained by irradiation and using it for various measurements and evaluations.

Example 9 The antioxidant tetrakis [methylene (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] methane was added to 100 parts by weight of the soft propylene ethylene random copolymer of Sample 4 described above. Then, the mixture was mixed sufficiently by stirring with a Henschel mixer. Thereafter, melt kneading was performed by an extruder, and a soft polyolefin was obtained by strand cutting. The obtained soft polyolefin was irradiated at the dose shown in Table 1. Table 1 shows the results obtained by shaping the soft polyolefin obtained by irradiation and using it for various measurements and evaluations.

Example 10 The antioxidant tetrakis [methylene (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] methane was added to 100 parts by weight of the soft propylene ethylene block copolymer of Sample 5 described above. Then, the mixture was mixed sufficiently by stirring with a Henschel mixer. Thereafter, melt kneading was performed by an extruder, and a soft polyolefin was obtained by strand cutting. The obtained soft polyolefin was irradiated at the dose shown in Table 1. Table 1 shows the results obtained by shaping the soft polyolefin obtained by irradiation and using it for various measurements and evaluations.

Comparative Example 7 The antioxidant tetrakis [methylene (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] methane was added to 100 parts by weight of the soft propylene ethylene block copolymer of Sample 1 described above. Then, the mixture was mixed sufficiently by stirring with a Henschel mixer. Thereafter, melt kneading was performed by an extruder, and a soft polyolefin was obtained by strand cutting. The obtained soft polyolefin was irradiated at the dose shown in Table 1. Table 1 shows the results obtained by shaping the soft polyolefin obtained by irradiation and using it for various measurements and evaluations.

Comparative Example 8 The antioxidant tetrakis [methylene (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] methane was added to 100 parts by weight of the soft propylene ethylene block copolymer of Sample 1 described above. 05 parts by weight Ethylene glycol dimethacrylate 5 parts by weight 1.3 parts by weight of bis (t-butylperoxyisopropyl) benzene 0.1 part by weight, and sufficiently mixed with a Henschel mixer. Thereafter, melt kneading was performed by an extruder, and a resin composition was obtained by strand cutting. The obtained resin composition was molded and the results used for various measurements and evaluations are shown in Table 1.

Example 11 10 parts by weight of the polypropylene homopolymer of Sample 2 was added to 90 parts by weight of the soft polypropylene resin of Sample 1, and the antioxidant tetrakis [methylene (3,5-di-tert-butyl-4-hydroxyphenyl) was used. ) Propionate] methane was blended in an amount of 0.05 part by weight, and the mixture was sufficiently stirred and mixed with a Henschel mixer. Thereafter, melt kneading was performed by an extruder, and a soft polyolefin was obtained by strand cutting. The obtained soft polyolefin was irradiated at the dose shown in Table 1. Table 1 shows the results obtained by molding the crosslinked soft polyolefin obtained by irradiation and using it for various measurements and evaluations.

[0055]

[Table 1]

Claims (4)

[Claims] 1. An elution component fractionated by a temperature-raising elution fractionation method, wherein the horizontal axis represents temperature (° C.) and the vertical axis represents an integrated weight ratio (% by weight).
A crosslinked soft polyolefin obtained by cross-linking a soft polyolefin having an elution component at 10 ° C. of from 10% by weight to 90% by weight with an electron beam and / or radiation. 2. The crosslinked flexible polyolefin according to claim 1, wherein the gel fraction is 1 to 75% by weight. 3. The method according to claim 1, wherein the soft polyolefin is a propylene ethylene block copolymer.
The crosslinked soft polyolefin according to the above item. 4. A soft polyolefin comprising 1 to 70% by weight of a polypropylene component and one monomer unit based on ethylene.
A propylene-based block copolymer comprising 99 to 30% by weight of a propylene-ethylene random copolymer component containing 0 to 60% by mole and 90 to 40% by mole of a monomer unit based on propylene. Item 4. The crosslinked soft polyolefin according to item 1.