JPH0441537A - Polyethylene resin composition - Google Patents

Abstract

PURPOSE:To obtain the title composition excellent in low-temperature impact resistance, heat resistance, fuel oil resistance, etc., by mixing four specified polyethylene resins having different properties, different compositions, etc. CONSTITUTION:A high-density polyethylene resin (A) having a density of 0.935g/cm<2> or above and a melt index of 0.01g/10min or above, a modified polyethylene resin (B) derived by grafting an unsaturated carboxylic acid (derivative) onto component A, a low-density linear polyethylene resin (C) having 5-30 short-chain branches per 1000 carbon atoms in the main chain, a density of 0.91-0.935g/cm<2>, a melt index of 0.1-50g/10min and a melting point as determined by differential scanning calorimetry of 115-130 deg.C, and an ultralow-density linear polyethylene (D) having 18-60 shortchain branches per 1000 carbon atoms in the main chain, a density of 0.89-0.91g/cm<3>, a melt index of 0.1-30g/10min and a melting point as determined by differential scanning calorimetry of 110-125 deg.C are mixed together in such amounts that B/(A + B) is 0.1wt.% or above, C/(A + B + C) is 2.5-75wt.%, and D/(A+B+C+D) is 5-40wt.%.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a specific polyethylene resin composition. In particular, it has excellent fuel oil resistance, impact resistance (especially impact resistance at low temperatures), and heat resistance, and various polyolefin resins such as polyethylene resin and polypropylene resin,
Polyamide resins such as nylon 6 and nylon 6-6, saponified copolymers of ethylene and vinyl acetate (EVOH)
), polyester resins such as polyethylene terephthalate resin and polybutylene terephthalate resin, various resin materials such as halogen-containing resins such as polyvinyl chloride resin and polyvinylidene chloride resin, and excellent affinity or adhesion with metal materials such as aluminum and iron. The present invention relates to a polyethylene resin composition useful in the field of packaging containers and industrial materials, where various polyethylene resin materials are used.

[Conventional technology]

Unsaturated carboxylic acids or their derivatives (for example, their anhydrides) have already been grafted onto ethylene homopolymers or ethylene-based copolymers containing ethylene as the main component! The techniques for doing so are well known.

Among them, modified ethylene polymers (modified polyethylene resins) graft-polymerized with acrylic acid, maleic acid, or maleic anhydride, polyamide resins (nylon), saponified ethylene-vinyl acetate copolymers (ethylene-vinyl alcohol copolymers), etc. Various laminates such as polar resins such as polymers, thermoplastic polyester resins, polyvinyl chloride resins, and polyvinylidene chloride resins, and metal foils such as aluminum foils (
It is used as an adhesive material in the coating of metal plates and tubes (films, sheets, etc.) and is in practical use.

In addition, additives such as various fillers, reinforcing agents, and pigments are added (
In addition to composite materials with additives), they are also often used for the purpose of imparting affinity and compatibility with matrix resins in polymer blends of different resins, and adhesion between different polymers.

Many modified ethylene polymers (modified polyethylene resins) of this type have been proposed, and it is difficult to satisfy all the various performances demanded by the market with a single modified ethylene polymer. Therefore, many proposals have been made to add various other specific polyolefin resins, elastomers, polymers having polar groups, or compounds having polar groups to modified ethylene polymers in order to impart these properties.

For example, compositions in which a soft resin is blended with a modified polyolefin resin (for example, Japanese Patent Publication No. 55-18251, Japanese Patent Publication No. 61-132345, Japanese Patent Publication No. 62-18258, Japanese Patent Publication No. IO-36217, etc.), modified ethylene-based Compositions in which a polymer is blended with another polymer (e.g., saponified ethylene-vinyl acetate copolymer, thermoplastic polyester resin) (e.g., JP-A-53-39381, JP-A-53-39381;
No. 2-124080 and No. 52-103480) have been proposed.

Furthermore, recently, linear low-density polyethylene resin (so-called L-LDPE), which has excellent environmental stress cracking resistance (ESCR), heat sealability, and low-temperature properties, has been used as a base material for modified ethylene polymers. It has been proposed to impart the above characteristics and improve heat resistance and adhesiveness by using it as a compounding material with an ethylene polymer (Japanese Unexamined Patent Publications Nos. 57-170940 and 57-883).
No. 51, 81-276302! No. 62-1825
No. 8, No. 62-25139, No. 82-119247).

Among these proposals, according to Japanese Patent Application Laid-Open No. 57-170940, the density is 0.900-0.940 g/cj
Medium/low pressure copolymer of ethylene and α-olefin of 02 to 20 mol 96 (a) 30 to 100 mol 96
and polyolefin resins other than (a) (b) 70 to O
It is a polyolefin resin composition in which at least one of the weight percentages is graft polymerized. Its purpose is to
An object of the present invention is to provide a polyolefin resin composition having excellent adhesive properties and environmental stress cracking resistance (ESCR). However, as shown in Examples 1 to 6 and Table 1, the density of the medium/low pressure polyethylene resin used is 0.
．． 920 g/d, and as described later, the density range of the linear ultra-low density polyethylene resin of the present invention (0,890 to 0.9
10g/cd) is not specifically disclosed. Furthermore, the total amount of the graft-modified linear low-density polyethylene resin and the unmodified linear low-density polyethylene resin in the composition is 80 to 100% by weight, and the proportion of these resins in the composition is extremely large. Furthermore, this invention cannot provide a material that is fully satisfactory in terms of fuel oil resistance, heat resistance, and rigidity, which are the objectives of the invention.

Also, Japanese Patent Publication No. 59-68351 (Japanese Patent Publication No. 84-561
No. 4) Publication has the same purpose as above, and uses 99.9-65% by weight of unmodified linear low-density polyethylene resin and 0.1-35% by weight of graft-modified linear low-density or high-density polyethylene resin. It is a laminate of a saponified ethylene-vinyl acetate copolymer, a polyamide resin or a thermoplastic polyester resin, and a polyolefin resin using a polyethylene resin composition consisting of the following. The linear low density polyethylene resin of the unmodified linear low density polyethylene resin and the graft modified linear low density polyethylene resin has a density of 0.910 to 0.9 BOg/cJ (preferably 0
．． 915 to 0.930 g/cJ, in the example, 0.92
6 g/c7) linear polyethylene resin is used.

Similarly, JP-A-61-278808 and JP-A-6216
In 7308 publication, the density is particularly 0.900 to 0.94.
To provide a manufacturing method for obtaining a modified product with high grafting efficiency by using a linear low-density polyethylene resin of 0 g / clr, reducing contamination of the obtained graft-modified product, and reducing crosslinking or oxidation reactions occurring during graft modification. It is. In addition, in JP-A-62-18258, the density is 0.9
The present invention provides a graft-modified polyolefin resin using a linear ultra-low density polyethylene resin produced by a gas phase/low pressure method of 10 g/cJ or less, and a mixture of the polyolefin resin and a different material. As this different material,
Unmodified elastomers (e.g., ethylene-propylene copolymer rubber), high-pressure low-density polyethylene resins, polyolefin resins such as ethylene-ethyl acrylate copolymers, ethylene-vinyl acetate copolymers, polyamide resins, ethylene-vinyl acetate copolymers, etc. Examples include saponified polymers (ethylene-vinyl alcohol copolymers).

Furthermore, in JP-A No. 62-25139, the product of melt index and melt tension and the high pressure low density polyethylene resin specified by the melt index and the density are 0.88C1-0,900g/CG? It is a composition consisting of a copolymer of ethylene and α-olefin (linear ultra-low density polyethylene resin) and acrylic acid or maleic anhydride kraft-modified polyethylene resin, and is a material with excellent moldability and adhesive properties. This is what we provide.

Moreover, in JP-A-62-10107, good adhesion and
It has a density of 0890 to 0.910 g/ctj, which has both heat sealability and heat resistance retention properties, and a weight average molecular weight/number average molecular weight of 2 to 15, and has a melt tension and melt resistance at a temperature of 180°C. A modified polyethylene resin made of a copolymer of ethylene having an index of 4 or less and an a-olefin having a carbon number of 4 or more, and a composition of the modified polyethylene resin and an unmodified polyethylene resin have been proposed.

Furthermore, JP-A-61-131345 and JP-A-6113
In No. 2377, the density is 0.8 SO ~ 0.91.0 g
/cd, is insoluble in boiling n-hexane, has a weight of 10 or more, and has a differential scanning calorimeter (Dif'Te
renLiaScanning Caloriraet
er) 1 to 40 rubber limbs per 100 parts by weight of a copolymer of ethylene and a-olefin having a maximum peak temperature of 100°C or higher, or a composition with a polyolefin resin containing the copolymer as a main component. A graft-modified enclosing resin and a laminate thereof have been proposed.

In addition, in Tokko Sho [io-3G942, polyethylene resin with a crystallinity of 4080 or higher or a polyethylene resin with a boiling point of 11en-
Graft modified polypropylene with hexane insolubility of 8080 or higher, weight 99° and crystallinity 5-309
It is a multilayer laminate consisting of a polyolefin resin composition consisting of an ethylene-α-olefin copolymer 1 to 0 with a density of 0870 to 0.910 g/ca and a nylon (polyamide resin) layer, and has interlayer adhesion. It has been proposed to provide laminates with significantly improved properties, particularly interlayer adhesion upon immersion in boiling water. However, the most preferred (crystallinity 5-30%, density 0.890-0.910g/
ci? ) -L tyrene α-olefin copolymer has a density of 0.87 when polymerized with a vanadium catalyst.
0 to 0.900 g/cJ, and the ethylene copolymerization ratio is 85 to 95 mol%, and the crystallinity is 5 to 5.
It lists 30% ethylene-butene-1 random copolymer.

[Problem to be solved by the invention]

However, no matter which modified polyethylene resin or its composition is used, the present invention provides a material that has excellent fuel oil resistance (gasoline resistance) and impact resistance, as well as good affinity and adhesion. It is extremely difficult to provide For example, materials used in industrial cans, containers for fuel such as gasoline, and related automobile parts that are used for long periods at low or high temperatures must fully satisfy all of the physical properties listed above. In particular, we have investigated these physical properties of polyamide resin layers and polyethylene resin layers used in multilayer polyethylene resin fuel containers (e.g., three types and five layers), such as polyamide resin, whose purpose is to prevent permeability of fuel oil such as gasoline. There are also strong demands on the adhesive layer, and the inventions proposed so far have not been able to sufficiently satisfy the requirements.

That is, in order to improve impact resistance, elastomers such as synthetic rubbers used in the production of graft-modified polyethylene resins or compositions thereof, ethylene α-olefin copolymers polymerized using vanadium base catalysts as main catalysts, or ethylene α-olefin copolymers with a density of 0. 880 to 0.910 g/c/, graft modified polyethylene resins or compositions thereof mainly composed of linear ultra-low density polyethylene resins have extremely poor fuel oil resistance when used at high temperatures for long periods of time, and For example, even if a graft-modified high-density polyethylene resin alone or a composition of a graft-modified high-density polyethylene resin and an unmodified high-density polyethylene resin or an unmodified low-density polyethylene resin can satisfy fuel oil resistance, it is extremely It is difficult to obtain excellent impact resistance, and it is also difficult to obtain good compatibility and adhesion with various resin materials and metal materials.

Further, taking the example of a large molded product manufactured by blow molding, during normal molding, debris is generated, and this debris is generally recycled and used from an economical point of view.

As described later, multilayer structures manufactured for the purpose of preventing the contents from permeating outside the container using barrier materials such as polyamide resin (PA) and saponified ethylene-vinyl acetate copolymer (EVOH). These barrier materials are usually also included in the plastic and will be recycled.

By the way, the impact resistance of these barrier materials is significantly inferior to that of relatively high-molecular-weight high-density polyethylene resins used in blow molding for boat fishing, and they have the disadvantage of being particularly poor in impact resistance at low temperatures. is known. Therefore, when recycling materials with poor impact resistance into layers of the main material in order to industrially and economically obtain containers consisting of multilayer structures, the impact resistance of the container deteriorates and the required performance is reduced. It becomes difficult to i&I.

Needless to say, in order to solve this problem, it is necessary to provide a new layer (Paris layer) for recycling Paris, or to create a bonding layer for bonding the main material (mainly polyethylene resin) and the barrier material. A method for recycling multi-layer Paris has been proposed. However, the former name is not economical as it requires new equipment, and the latter case requires
PA in Paris (when PA is used as a barrier material)
It is undesirable because it reacts with the graft-modified polyolefin resin and causes gelation and has poor long-term adhesive durability.

For these reasons, in order to prevent the impact resistance of the resulting product from deteriorating even if the multilayered material is recycled, for example, Japanese Patent Publication No. 34461 (Japanese Patent Publication No.
113878) and Japanese Patent Publication No. 42625 (Japanese Unexamined Patent Publication No. 55-91834), it has been proposed to use polyolefin resins or polyamide resins that have specific adhesive properties. However, the long-term fuel oil resistance of each resin is poor and impractical.

Based on the above, the present invention solves all of these drawbacks; in other words, even after long-term use, it not only has good fuel oil resistance in a high-temperature atmosphere, but also has good impact resistance (especially at low temperatures). The purpose is to obtain a material that is extremely loose, and also has extremely low affinity with recycled materials during recycling of Paris generated during molding processing, and extremely low adhesion with barrier materials such as polyamide resin. It is.

[Means and effects for solving the problems] According to the present invention, these problems are (A) Density 0.935
g/cl? That's all, Ka Melt Index [Month S
Measured under conditions 4 according to K7210, hereinafter rMN
(B) a modified polyethylene in which at least one monomer selected from the group consisting of unsaturated carboxylic acids and derivatives thereof is grafted to the high-density polyethylene resin; Resin, (C) The number of short chain branches per 1000 carbon atoms in the main chain is 5 to 30, and the density is 0.910 g/cm3
The above is 0.935g/cI? less than M
1 to 50 g/10 minutes, and a differential scanning calorimeter [Diffcrentia! Scanning Ca
lorimeter, hereinafter referred to as rDSCl] method, and (D) the number of short chain branches per 1000 carbon atoms in the main chain is 18 to 60, And the density is 0.890g/cm
3 or more, but less than 0.91.0 g/cJ, Ml is 0.1 to 30 g/10 min, and DS
A composition consisting of a linear ultra-low density polyethylene resin having a melting point of 110 to 125°C by Method C, and the composition ratio of the modified polyethylene resin in the total amount of the high density polyethylene resin and the modified polyethylene resin is at least 0.1% by weight. % and
And the composition ratio of the high density polyethylene resin, modified polyethylene resin and linear low density polyethylene resin is 25 to 25.
75 weight ff 19°, and the composition ratio of the linear ultra-low density polyethylene resin in the whole composition is 50 to 40.
This problem can be solved by using a polyethylene resin composition having a heavy ME of 90% and a composition ratio of the grafted monomer in the total composition of 0.001 to 5.0% by weight. The present invention will be explained in detail below.

(^> High-density polyethylene resin The high-density polyethylene resin used in the present invention and the high-density polyethylene resin used as a material in the production of the modified polyethylene resin described below are either ethylene alone or ethylene and carbon atoms of 3 to 12 carbon atoms (preferably is 3-8
It is obtained by homopolymerization or copolymerization of α-olefins (2) in the presence of a so-called Phillips catalyst or Ziegler catalyst, and is generally produced at a pressure of from normal pressure to about 100 kg/cm (medium to low pressure polymerization). Preferred a-olefins include propylene, butene-1, hexene-1,4-methylhentene-1 and octene-1).
can give. The copolymerization ratio is at most 65%, preferably 60% or less.

1000 carbon atoms in the main chain of this high density polyethylene resin
The number of short chain branches per individual is at most 20.

In addition, the density is o, 935 g/cJ or more, and 0937
g/c♂ or more is preferable, especially 0.940 g/ca
The above is preferable. If a polyethylene resin having a density of less than 0.935 g/cj is used, products molded using the resulting composition will be inferior in terms of rigidity, heat resistance, fuel oil resistance, surface hardness, etc.

Furthermore, M I is 0.01 g/10 min or more, preferably 0.015 g/10 min or more, especially 0.01 g/10 min or more.
02g/10 minutes or more is suitable. M+ or 0.01g
If the time is less than 10 minutes, the moldability is not good. Also,
The upper limit is not particularly limited, but is usually 50 g/10 minutes in terms of mechanical strength, and preferably 35 g/10 minutes or less.

In particular, in the case of the grafted high-density polyethylene resin described below, if the Ml is less than 0.12710 minutes, the MI of the resulting grafted high-density polyethylene resin will generally decrease depending on the graft modification conditions. It becomes even lower than the Ml of the density polyethylene resin, resulting in lower molding processability and significantly lower compatibility when producing a mixture with a non-grafted high density polyethylene resin, making it impossible to obtain a uniform composition. Therefore, the Fwl 1 of the high-density polyethylene resin used for graft modification is generally preferably 0.05 g/10 minutes or more, and particularly preferably 0.1 g/10 minutes or more.

These high-density polyethylene resins may be used alone or in combination of two or more.

The grafted high-density polyethylene resin of the present invention [hereinafter referred to as "graft-modified high-density polyethylene resin"] is obtained by treating the high-density polyethylene resin with an unsaturated carboxylic acid and/or its derivative described below in the presence of a radical initiator. You can get it by doing At this time, a synthetic resin or elastomer (rubber), which will be described later and has an affinity with the high-density polyethylene resin to be grafted, may be present.

(B) Unsaturated carboxylic acids and derivatives thereof The unsaturated carboxylic acids and derivatives thereof used in the grafting treatment in the present invention include -basic unsaturated carboxylic acids and dibasic unsaturated carboxylic acids and metal salts thereof;
Mention may be made of amides, imides, esters and anhydrides.

Among these, the -basic unsaturated carboxylic acid generally has at most 30 carbon atoms (preferably 25 or less).

Further, the number of carbon atoms in the derivative is usually at most 20 (preferably 15 or less). Furthermore, the dibasic unsaturated carboxylic acid generally has at most 30 carbon atoms (preferably 25 or less). Further, the number of carbon atoms in the derivative is usually at most 30 (preferably 25 or less).

These unsaturated carboxylic acids and their representative examples are described in JP-A No. 6
It is described in the specification of Publication No. 2-10107 from page 3, bottom right column, line 8 to page 4, top right column, line 12.

Among these unsaturated carboxylic acids and their derivatives, acrylic acid, methacrylic acid, maleic acid and its anhydride, 5-norbornene-283 dicarboxylic acid and its anhydride, and glycidyl methacrylate are preferred;
Particularly preferred are maleic anhydride and 5-norbornenic anhydride.

(C) Radical initiator Further, the radical initiator used in the production of the graft-modified high-density polyethylene resin in the present invention usually has a decomposition temperature of 100°C or higher with a half-life of 1 minute, and 1
A temperature of 03°C or higher is desirable, and a temperature of 105°C or higher is particularly preferred. Suitable radical initiators include dicumyl peroxide, benzoyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl-
2,5-di(tertiary-butylperoxy)hexane, 2
．． Examples include organic peroxides such as 5-dimethyl-2,5-di(tertiary-butylperoxy)hexane-3, lauroyl peroxide, and tertiary-butylperoxybenzoate.

(D) Synthetic resin and elastomer When producing the graft-modified high-density polyethylene resin in the present invention, the synthetic resin and elastomer that are grafted together with the high-density polyethylene resin to be crafted are those that have affinity with the high-density polyethylene resin.

Among these, synthetic resins include high-pressure low-density polyethylene resin, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, ethylene-methyl acrylate copolymer, and ethylene-vinyl acetate copolymer. Examples include copolymers of ethylene and other vinyl monomers such as ethyl acrylate copolymer, ethylene-butyl acrylate-1 copolymer, and ethylene-methyl methacrylate copolymer.

In addition, examples of elastomers include ethylene-propylene copolymer rubber, ethylene-propylene-diene ternary copolymer rubber, and ethylene-butene-1 copolymer rubber.
α-heolefin copolymer rubber, polyisobutylene rubber,
Polyurethane rubber, styrene-butadiene copolymer rubber,
Examples include synthetic rubber such as polybutadiene rubber and natural rubber.

(E) Ratio In producing the graft-modified high-density polyethylene resin of the present invention, the high-density polyethylene resin to be grafted 1
The ratio of the unsaturated carboxylic acid and/or its derivative and the radical initiator to 00 parts by weight is as follows.

For unsaturated carboxylic acids and derivatives thereof, the total amount thereof is generally 0. OJ ~ 5,0 parts by weight, 0
．． Old to 3,0 times part is preferable, especially 0.02 to 2.0
Parts by weight are preferred. If the total amount of the unsaturated carboxylic acid and its derivatives is less than 0.01 part by weight, the graft modification will be insufficient, causing problems in terms of affinity or adhesion, which is the object of the present invention. On the other hand, 5
．． If the amount exceeds 0 parts by weight, the resulting graft-modified high-density polyethylene resin may become gelled, turn blue or deteriorate, and the performance improvement aimed at by the present invention may not be achieved.

Further, the ratio of the radical initiator is usually 0.001 to 1.
0 parts by weight, preferably 0.005 to 1.0 parts by weight, particularly preferably 0.005 to 0.05 parts by weight.

If the proportion of the radical initiator is less than 0.001 part by weight, the effect of graft modification will be insufficient, and not only will it take a long time to completely carry out graft modification, but also unreacted substances will be present. On the other hand, if it exceeds 10 parts by weight,
It is undesirable because it causes excessive decomposition or crosslinking reaction.

Furthermore, when the synthetic resin or elastomer is used, its proportion in the total amount with the high density polyethylene resin is generally at most 15% by weight, and particularly preferably 10% by weight or less. If the proportion of the synthetic resin and/or elastomer in the total amount of the high-density polyethylene resin exceeds 15% by weight, the basic properties of the high-density polyethylene may be impaired.

(F) Production of graft-modified high-density polyethylene resin The graft-modified high-density polyethylene resin of the present invention comprises the above-mentioned high-density polyethylene resin (as the case may be, a synthetic resin and/or elastomer), an unsaturated carboxylic acid and/or a derivative thereof, and an unsaturated carboxylic acid and/or a derivative thereof. /cal initiator within the above-mentioned ratio range.

The method of processing is JP-A-62-10170 and JP-A-6
] -132345, a known method may be employed.

Processing methods include extruders, Banbury mixers,
A method of kneading high-density polyethylene resin in a molten state using a kneader, a solution method of dissolving a polymer such as high-density polyethylene resin in an appropriate solvent, and a method of kneading polymers such as high-density polyethylene resin in a suitable solvent. Examples include a slurry method in which particles are suspended, or a so-called gas phase grafting method.

The treatment temperature may be selected appropriately, taking into account the deterioration of polymers such as high-density polyethylene resin, the decomposition of unsaturated carboxylic acids and their derivatives, and the decomposition temperature of the Rancar initiator used, or the treatment temperature may be selected as appropriate, taking into account the decomposition temperature of the polymer such as high-density polyethylene resin, the decomposition temperature of the Rancar initiator used, or For example, the temperature is usually 100 to 350℃, and 150 to 300℃.
The temperature is preferably from 180 to 300°C.

Of course, in order to produce a modified high-density polyethylene resin or to improve the performance of the graph of the present invention in this way, there have been previously known Treatment methods, for example, treatment with an epoxy compound or a polyfunctional compound containing an amino group or a hydroxyl group during or after graft modification, further heating and washing, and unreacted monomers.
(unsaturated carboxylic acids and derivatives thereof) and various by-product components may be removed.

In addition, the manufacturing method of the linear low density polyethylene resin and the linear ultra low density polyethylene resin used in the present invention, which will be described later, is widely known, and in recent years, it has been used industrially by slurry polymerization method or gas phase polymerization method. (G) Linear low-density polyethylene resin The linear low-density polyethylene resin used in the present invention has a density of 0.6 (G) Linear low-density polyethylene resin.
910~0.935 glci, MI is 0.1~
5 (Ig/10 min. Also, the melting point by DSC measured by the method described below is 115 to 130 ° C., and the number of short chain branches per 1000 carbon atoms in the main chain is 5 to 30. It is something.

The linear low density polyethylene resin is manufactured industrially, and the manufacturing method thereof is well known. In particular, it has excellent environmental stress cracking resistance, transparency, heat sealability, brittleness resistance, and low-temperature properties, so it is used in a wide range of fields (for example, packaging materials such as films, industrial materials such as vibrators, etc.) ).

The linear low-density polyethylene resin is produced by copolymerizing ethylene and an α-olefin described below using a so-called Ziegler catalyst by any of the gas phase method, solution method, and slurry method. .

The density of the linear low density polyethylene resin is 0.910g
/cI+? The above is less than 0.935 g/cj, preferably 0.912 g/cm3 or more, and 0.93
Less than 5 g/cj is preferred, especially 0.913 g/c11
? However, it is preferably less than 0.935 g/cm3.

In addition, MI is 0.1 to 50 g/10 minutes, and 0.2 to 50 g/10 minutes.
40g/10 minutes is desirable, especially 0.2-30g/
10 minutes is preferred. M of linear low density polyethylene resin
If I is less than 0.1 g/10 minutes, moldability is poor. On the other hand, if it exceeds 50 g/10 minutes, the resulting composition will have poor mechanical strength.

Furthermore, the melting point of the linear low density polyethylene resin measured by DSC is 115 to 130°C, preferably 118 to 130°C, and particularly preferably 118 to 125°C. D
If the SC melting point is lower than 115°C, long-term fuel oil resistance at room temperature is poor.

On the other hand, when the temperature exceeds 130°C, the density exceeds the upper limit of the range of the present invention.

Furthermore, the linear low density polyethylene resin has 1 carbon atom in its main chain.
The number of short chain branches per 1,000 pieces is 5 to 30, preferably 5 to 25. Even if the number of short chain branches per 1000 carbon atoms in the main chain is less than the lower limit or exceeds the upper limit,
In either case, the uniformity of the composition of the present invention becomes insufficient, which is undesirable. In other words, when using a composition using a linear low-density polyethylene resin in which the number of branches per 1000 carbon atoms in the main chain is outside the above range, it is especially important to note the long-term fuel oil resistance. , not only is there a large decrease in tensile elongation, but if heat resistance (specifically, a durability test in an atmosphere of 100°C or higher) is taken into account, physical properties will further deteriorate. Both of these are considered to be due to the non-uniformity of the composition.

(11) Linear ultra-low density polyethylene resin Furthermore, the linear ultra-low density polyethylene resin used in the present invention is
Crystallinity obtained by polymerization using a conventionally known vanadium catalyst system from several qo to about 3006
Unlike the low crystallinity ethylene-α-olefin random copolymer (density 086-0.91 g/cj),
For example, JP-A-57-68306, JP-A-59-2301
It is a linear low-density polyethylene resin produced by a slurry method or a gas phase method using a stereoregular catalyst (so-called Ziegler catalyst) as described in Publications No. 1 and No. 62-109805.

The density of the linear super-density polyethylene resin in the present invention is 0.890 g/c? Above, 0.910g/cm
The Ml is 01 to 30 g/10 min, the melting point by DSC is 110 to 125°C, and the number of short chain branches per 1000 carbon atoms in the main chain is 8 to 60.
It is a linear low-density polyethylene resin.

In the present invention, the density of the polyethylene resin is 0.8
If it is less than 90 g/cj (=, there is a problem in terms of fuel oil resistance of the resulting composition. On the other hand, if it exceeds 0.910 g/c♂, the impact resistance of the resulting composition is insufficient. From these facts, the density is 0892~0.910 z/cI
? Later is preferable.

Further, if the MI of the resin is less than 0.01 g/10 minutes, it is not preferable in terms of moldability and processability. On the other hand, 30g/
If it exceeds 10 minutes, there may be problems with impact resistance. For these reasons, it is desirable that the M I be 0.1 to log/min, particularly preferably 0.2 to 5.0 i/10 min.

Sarani, DSC (weighed approximately 5111 g of sample,
Set this in a DSC measuring device, raise the temperature from room temperature to 200°C at a rate of 10°C/min, and then
The melting point is 110 to 125.The melting point is 110 to 125. ℃. In particular, 1
Preferably, it has a temperature of 12 to 125°C. If the melting point is lower than 110°C, the resulting composition will have insufficient heat resistance. On the other hand, if the temperature is higher than 125°C, the effect of improving impact resistance is poor.

Moreover, the number of short chain branches per 1000 carbon atoms in the main chain of the polyethylene resin is 18 to 60, and 18 to 58.
The number is preferably 18 to 55, especially 18 to 55. If the number of short chain branches per 1,000 carbon atoms in the main chain is less than 18, there will be problems in terms of the impact resistance that can be obtained. On the other hand, if the number exceeds 60, the fuel oil resistance will be significantly inferior. In both the linear ultra-low density polyethylene resin and the linear low density polyethylene resin, the term "short chain" refers to an alkyl group having substantially 1 to 10 carbon atoms (preferably 1 to 6 carbon atoms). It consists of the base.

In addition, from the viewpoint of improving impact resistance, the initial tensile modulus of the polyethylene resin is 2 x 10"kg f/
cd or less (preferably 1.5X 103kg f
/cd) is preferred.

The linear ultra low density polyethylene resin and the linear low density polyethylene resin are obtained by copolymerizing ethylene and α-olefin using a Ziegler catalyst. The α-olefin usually has 3 to 12 carbon atoms.
(preferably 3 to 8) is desirable. Preferred alpha-olefins include propylene, butene-1, pentene-1, hexene-1,4-methylpentene-1 and octene-1.

(c) Composition ratio In the present invention, the composition ratio of the modified polyethylene resin in the total amount of the high-density polyethylene resin and the modified polyethylene resin is at least 0.01% by weight, and 1.0% by weight.
0 double double. A weight of 25° or more is desirable, and a weight of 25° and 9° is especially preferable. If the composition ratio of the high-density polyethylene resin and the modified polyethylene resin is less than 0.1 weight Qo, a polyethylene resin composition that satisfies the affinity or contactability with the resin materials, metal materials, etc., which is the object of the present invention, is obtained. I can't do anything.

Furthermore, the composition ratio of the linear low-density polyethylene resin in the total amount of the high-density polyethylene resin, modified polyethylene resin, and linear low-density polyethylene resin is 2.5 to 2.5.
75% by weight, 5.0-75% by weight? δ is preferable,
Particularly suitable is 5,0 to 60 weight 96. If the composition ratio of the linear low-density polyethylene resin to the total amount of the high-density polyethylene resin, modified polyethylene resin, and linear low-density polyethylene resin is less than 25% by weight, the uniformity of the composition in the entire composition will be poor. On the other hand, if it exceeds 75% by weight, the heat resistance and long-term fuel oil resistance at high temperatures will be poor.

The composition ratio of the cotton linear ultra-low density polyethylene resin in the polyethylene resin composition of the present invention is 50 to 40% by weight.
It is preferably 50 to 375 weight O8, particularly preferably 60 to 37.5 weight O8. If the composition ratio of the linear ultra-low density polyethylene resin in the polyethylene resin composition is less than 50% by weight, the resulting composition will have poor impact resistance. On the other hand, if the weight exceeds 40% by weight, the fuel oil resistance (particularly the fuel oil resistance at 40° C.) is unfavorably deteriorated.

(K) Composition and method for producing the same The polyethylene resin composition of the present invention has a high molecular weight. !
: One-degree polyethylene resin, modified polyethylene resin, linear low-density polyethylene resin, and linear ultra-low-density polyethylene resin, each within the above composition ratio range.

In general, when a monomer (in the case of the present invention, an unsaturated carboxylic acid or its derivative) is graft-modified onto a polymer (in the case of the present invention, high-density polyethylene resin), seven polymers are added to all polymers. Grafting is difficult, and some polymers exist that are not grafted. In the present invention, the ungrafted high-density polyethylene resin may be used as it is without separation. Further, a high density polyethylene resin which has not been subjected to graft treatment may be further blended.

Alternatively, high-density polyethylene resin, linear low-density polyethylene resin, and linear ultra-low-density polyethylene resin may be mixed in advance, and the resulting mixture and modified polyethylene resin may be mixed, or all composition components may be mixed at the same time. good.

In any of the above cases, the proportion of the grafted monomers in the polyethylene resin composition of the present invention is 0.001 to 5.0% by weight as a total amount thereof, and 0.001 to 5.0% by weight.
01 to 2.0% by weight is desirable, especially 0.02 to 1% by weight.
．． 0% by weight is preferred. If the proportion of the grafted monomers in the polyethylene resin composition is less than o, oot% by weight in total, the various effects of the present invention cannot be fully exhibited. On the other hand, 5.0% by weight
Even if it exceeds this, the effects of the present invention cannot be further improved.

In producing the polyethylene resin composition of the present invention, antioxidants, heat stabilizers, ultraviolet absorbers, and lubricants commonly used in the field of polyolefin resins are used to the extent that they do not substantially impair the effects of the composition. , antistatic agent,
Additives such as pigments (colorants) can be added.

Mixing methods for producing the composition include various mixing methods commonly used in the field of synthetic resins;
That is, tri-blending using a mixer such as a tumbler or Henschel mixer, an extruder, or a kneader.
, a Banbury mixer, and a method of melt-kneading using a kneader such as a roll. At this time, a more uniform composition can be obtained by performing two or more of these mixing methods (for example, a method of tri-blending in advance and further melt-kneading the resulting mixture) (L) Processing method The polyethylene resin composition of the present invention obtained in this way can be applied to containers such as industrial cans and fuel oil tanks such as gasoline, and can be processed by the hollow forming method, which is generally used as a molding method. It can be easily formed into a desired shape, and an article with unprecedented impact resistance can be obtained. In addition to hollow formability,
Various parts such as caps and various industrial parts can be easily obtained by injection molding, compression molding, etc.

Furthermore, in recent years, polyethylene resin has come to be used in automobile fuel oil tanks, and polyamide resin (PA) is being developed as a means to prevent fuel oil from permeating through these tanks. ) as a barrier layer in multilayer fuel oil tanks (PA
) and the main material (mainly high-density polyethylene resin), the polyethylene resin composition of the present invention is particularly useful because it has both excellent impact resistance (especially impact resistance at low temperatures) and fuel oil resistance. It is. In this case, the multilayer structure is A/C/E, where A is the main material, B is the barrier material, and C is the composition of the present invention.

A/C/B/C/A, A/C/B/C, C, /B/C/
There are three or more layers such as A (of course, a layer including a firmness layer generated by blow molding, for example, may be provided between the A and C layers in these structures).

In addition, in order to improve the affinity and adhesiveness of the polyethylene resin composition of the present invention with barrier resins such as PA, it is preferable to use a C/B or C/B/C bilayer or It can be used as a laminate consisting of two or three layers.

[Examples and comparative examples]

The present invention will be explained in more detail below with reference to Examples.

In addition, in the examples and comparative examples, the impact resistance is JIS
According to the K7110 method, the notched isot impact strength was measured at temperatures of 23° C. and -35° C. using a press plate with a thickness of 3+ am. In addition, heat resistance, flame resistance, 1 oil resistance (durability test) was determined by JI made from a press plate with a thickness of 2 dragons.
Place the S No. 2 test piece in a gear oven at 110°C.
After being allowed to stand still for 2000 hours and immersed in commercially available regular gasoline at 40°C for 2000 hours, the tensile elongation at break (E,) was measured according to the JIS K7113 method. E ) and the rate of decline (
Eo-E,) was calculated.

In addition, the modified g/
Powdered high-density polyethylene resin [hereinafter referred to as rH]
0.010 parts by weight of 2,5-dimethyl-2,5-tertiary-butylperoxyhexane as a radical initiator was added to 100 parts by weight of DPE(i)J, and 2.5 parts by weight was added using a Henschel mixer. A tri-blend was performed for a minute.

Then, maleic anhydride [hereinafter r PvI A H
037 parts by weight (referred to as j) was added to the mixture, and tri-blending was performed for 3 minutes using a Henschel mixer. The resulting mixture was melt-kneaded using an extruder (diameter 40 m+s) at a resin temperature of 265°C and pelletized to produce a modified polyethylene resin [hereinafter referred to as modified P E (A) J].

The modified P E (A) was analyzed by infrared absorption spectroscopy [hereinafter referred to as r
The grafted MA was measured by the IR method.
The amount of R was 0.33% by weight.

and has a density of 1,955 g/cj [hereinafter referred to as rHDPE(ii)J]
A modified polyethylene resin [hereinafter referred to as "modified PE (B) J]" was produced by tri-blending and melt mixing in the same manner as in the case of modified PE (A), except that the modified PE (B) was used. ), the amount of grafted MAR measured by IR method was 0.31% by weight, g/10 min, and the density was 0.944 g/cd [hereinafter referred to as rHDPE(iii)]. ] Tri-blend and melt-kneading were carried out in the same manner as above, except that modified polyethylene resin [hereinafter "modified P
E (C)J] was produced. The modified P E (C
), the amount of grafted MAH measured by IR method was 0.31% by weight, 2.0 g/10 min, and the density was 0.895 g/c1? The melting point (m
, p,) is 97°C, and the number of branches [hereinafter simply referred to as "number of branches"] or 70 per 1000 carbon atoms in the main chain is a copolymer of ethylene and butene] [hereinafter r L V
In addition to using L D P E (a) J],
Perform triblending and melt mixing in the same manner as above,
Modified product of polyethylene resin composition [hereinafter referred to as [modified PE (D
)J was manufactured. The modified P E (D) is IR
The amount of grafted t-MAH determined by the method was 0.
It weighed 29 and weighed 6. In addition, the density of linear low density polyethylene resin (hereinafter referred to as rL-LDPEJ) is 0.929z/ca, and the density of M-0.890g/ca.
A copolymer of ethylene and butene-1 [hereinafter referred to as rLLDPE (1) J], which has a melting point of 120 ° C by DSCd, and has a branching number of 24 [rLLDPE (1) J] and a density of 0.92]. g/cIli', MFR is 20 g/10 min, and the melting point is 120°C by DSC method.
A copolymer of ethylene and buteno-1 [hereinafter referred to as rLLDPE (II) J
] was used.

Furthermore, linear ultra-low density polyethylene resin [rVLD
PEJ] is a linear ultra-low density polyethylene resin (referred to as LVLDPE), which is made of a solid tactile component containing titanium and an aluminum compound system, has a melting point of 120°C according to the DSC method, and has 30 branches. (a) J] and a linear ultra-low density polyethylene resin having a temperature of mp, 116°C, and 37 branches.
rLVLDPE(b)J] was used.

Examples 1 to IO1 Comparative Examples 1 to 7 Modified polyethylene resins whose types and mixing ratios are shown in Table 1 [hereinafter referred to as "modified products"],
High density polyethylene resin (hereinafter referred to as rHDPEJ)
, L-LDPE and LVLDPE were pre-triblended for 2 minutes using a Henschel mixer. Using an extruder (diameter 50 mm) equipped with a dalmage screw, each of the obtained mixtures was melt-kneaded at a resin temperature in the range of 200 to 210°C to form a pellet-shaped polyethylene resin composition (the abbreviation of each composition is (shown in Table 1) were produced. Test specimens were prepared from each of the obtained polyethylene resin compositions to measure the Izot impact strength and heat resistance and fuel oil resistance, and the durability was tested as Izot impact strength and heat resistance and fuel oil resistance tests at temperatures of 23°C and -35°C. The tensile elongation at break (El) subjected to the test and the tensile elongation at break (Eo) of the specimens not subjected to the durability test were measured. In addition, polyamide resin (nylon 6)
The initial adhesion and adhesion durability were measured. The results are shown in Table 2.

(Part 1) Table (Part 2) * ** The degree of swelling on the gasoline side was large, and some of the test specimens varied, and some of the specimens were dissolved in the liquid, causing deformation. In order to evaluate the resin composition, polyethylene resin compositions obtained in Reference Examples and Comparative Examples described later are used as control examples, and the effects of the present invention are clarified by comparing the adhesion with polyamide resin.

[Reference example and comparative example]

The adhesiveness is 40y for the inner layer and outer layer respectively.
Nylon 6 (manufactured by Toshi Co., Ltd., trade name Amiran-CM 104) was used for the XRA and intermediate layers using a multilayer coextrusion device equipped with a 30-order table extruder and a multilayer T-die for two types and three layers.
B) has two or three layers, with an intermediate layer having a thickness of about 0.10 mm, and inner and outer layers each having a thickness of 0.20 mm made of the polyethylene resin composition prepared in the example or comparative example. The sheet was made at a molding temperature of 230°C. For each obtained sheet specimen (width 10, length 150 om), T-peel was performed at the nylon 6 interface using a Tensilon type tensile tester at a peel rate of 50+n+s/min to determine the peel resistance value before treatment. (kg/c+n width) was determined. Furthermore, as an evaluation of heat resistance and fuel oil resistance regarding adhesion, each multilayer section similar to the above was placed in an oven at 110°C for 96 hours, and then placed in a commercially available regular gasoline at 40°C for 2,000 hours.
After being immersed for a period of time, the adhesion to nylon 6 was similarly determined after treatment. The results are shown in Table 3.

Table 3 (Part 1) a) Sheet cutting Table 3 (Part 2) a) Sheet cutting b) Gasoline swelling degree is large and variation C) Part of the test piece is melted or deformed by gasoline d) End face Peeling occurs [Effects of the Invention] The polyethylene resin composition of the present invention exhibits the following effects.

(1) Impact resistance at room temperature Not only is the impact resistance weak at room temperature, but also the impact resistance at low temperatures (for example, -35°C) is good.

(2) Heat resistant and fuel oil resistant.

3) Polyethylene resin, -polyamide resin, EVOH
1. It has good affinity and adhesion with various resin materials such as thermoplastic polyester resin and various metals, and in particular, a laminate in which the composition of the present invention is interposed between polyethylene resin and polyamide resin. You can also create one. The laminate has excellent heat resistance and fuel oil resistance.

The polyethylene resin composition of the present invention exhibits the above-mentioned effects and can be used in a wide variety of fields. In particular, typical uses that can be used in various fields by adhering to or intervening with the various resin materials and various metal materials mentioned above are shown below.

(1) Scale containers and other parts that use fuel oil, such as gasoline tanks.

Various packaging materials.

Various industrial materials.

Claims (1)

[Scope of Claims] (A) A high-density polyethylene resin having a density of 0.935 g/cm^3 or more and a melt index of 0.01 g/10 minutes or more, (B) a modified polyethylene resin grafted with at least one monomer selected from the group consisting of saturated carboxylic acids and derivatives thereof; (C) the number of short chain branches per 1000 carbon atoms in the main chain is 5;
~30 pieces, and the density is 0.910 g/cm^3 or more but less than 0.935 g/cm^3, the melt index is 0.1 to 50 g/10 minutes, and the differential scanning calorific value is A linear low-density polyethylene resin having a melting point of 115 to 130°C by measurement method, and (D) the number of short chain branches per 1000 carbon atoms in the main chain is 1.
8 to 60 pieces, and the density is 0.890g/cm^3
However, the linear ultra-low density is less than 0.910 g/cm^3, the melt index is 0.1 to 30 g/10 minutes, and the melting point is 110 to 125 °C by differential scanning calorimetry. A composition consisting of a polyethylene resin, wherein the composition ratio of the modified polyethylene in the total amount of the high density polyethylene resin and the modified polyethylene resin is at least 0.1% by weight, and the high density polyethylene resin and the modified polyethylene resin The composition ratio of the linear low-density polyethylene resin in the total amount of the linear low-density polyethylene resin is 2.5 to 75% by weight, and the composition of the linear ultra-low-density polyethylene resin in the total composition is 2.5 to 75% by weight. A polyethylene resin composition in which the proportion of the grafted monomer is 5.0 to 40% by weight, and the proportion of the grafted monomer in the entire composition is 0.001 to 5.0% by weight.