JPH03237144A - Polyethylene based resin composition - Google Patents

Abstract

PURPOSE:To obtain a composition having good resistance to fuel oil under high temperature over a long period and capable of providing a vehicle member, etc., jointly having impact resistance, affinity and adhesion by blending specific three kinds of polyethylene resins. CONSTITUTION:The aimed composition obtained by blending (A) a high-density polyethylene having >=0.930g/cm<3> density and >=0.01g/>=10min melt flow rate with (B) a modified polyethylene resin obtained by grafting a monomer selected from an unsaturated carboxylic acid (derivative) to the component A, (C) a linear ultra-low-density polyethylene resin having 18-60 branched number of short chain per 1000 carbon of main chain, 0.890-0.91g/cm<3> density, 0.1-30g/10min melt flow rate and 110-125 deg.C melting point by a differential scanning calorimeter method at amounts of the component B to the components A and B of 0.1wt.%, component C in total components of 5.0-35wt.% and graft monomer in total components of 0.001-5.0wt.%.

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)
), various resin materials such as polyester resins such as polyethylene terephthalate resin and polybutylene terephthalate resin, halogen-containing resins such as polyvinyl chloride resin and polyvinylidene chloride resin, and 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, industrial materials, etc. where various polyethylene resin materials are used. [Prior Art] The technique of graft polymerizing an unsaturated carboxylic acid or a derivative thereof (for example, an anhydride thereof) onto an ethylene homopolymer or an ethylene copolymer containing ethylene as a main component is already 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. Polymer, thermoplastic polyester resin,・
It is used as an adhesive material in the coating of various laminates (films, sheets, etc.) such as polar resins such as polyvinyl chloride resin and polyvinylidene chloride resin, and metal foils such as aluminum foil, as well as metal plates or metal tubes, and has not been put into practical use. There is. 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, but it is no longer possible to satisfy all the various performances demanded by the market with a single modified ethylene polymer. Therefore, many proposals have been made to blend various other specific polyolefin resins, elastomers, polymers having polar groups, compounds having polar groups, etc. with modified ethylene polymers in order to impart this performance. 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. 60-36217, etc.) and modified ethylene-based Compositions in which other polymers (e.g., saponified ethylene-vinyl acetate copolymer, thermoplastic polyester resin) are blended with the polymer (e.g., JP-A-53-39381, JP-A-53-39381;
No. 124080, No. 52-103480) have been proposed. Furthermore, in recent years, 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 a polymer.
No. 1, No. 61-276808, No. 62-18258, No. 62-25139, No. 62-119247). Among these proposals, according to Japanese Patent Application Laid-Open No. 57-170940, the density is 0.9 (10-0,940 g/c
Medium/low pressure copolymer of ethylene which is rn' and 0.2 to 20 mol% α-olefin (a) 30 to ioo
Weight% and (1 bl of polyolefin resin other than al)
70 to 0% by weight of at least one of the polyolefin resin compositions is kraft polymerized. The objective is to provide a polyolefin resin composition with excellent adhesion and environmental stress cracking resistance (ESCR). However, as shown in Examples 1 to 613 and Table 1, the density of the medium/low pressure polyethylene resin used is 0.920 g/crr1'', and as described later, the linear ultra low pressure polyethylene resin of the present invention Density Density range of polyethylene resin (
o, sso~0.910 g/crn') is not specifically disclosed. Moreover, the total amount of the Kraft-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. However, with this invention, it is not possible to obtain a product that is fully satisfactory in terms of fuel oil resistance, heat resistance, and rigidity, which are the objectives of the present invention. In addition, Japanese Patent Publication No. 59-68351 (Japanese Patent Publication No. 64-561
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 0.960 g/cm3 (preferably 0
．． A cotton-like polyethylene resin of 915 to 0.930 g/crd (0.926 g/crd in the example) is used. Similarly, JP-A-61-276808 and JP-A-62-1
In 67308, the density is particularly 0.900 to 0.9.
Provides a manufacturing method for obtaining a modified product with high grafting efficiency by using a linear low-density polyethylene resin of 40 g/cm' and reducing contamination of the resulting graft modified product and crosslinking or oxidation reactions that occur during graft modification. It is something to do. 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/crd or less, a mixture of the polyolefin resin and a different material, and the like. These different materials include unmodified elastomers (e.g., ethylene-propylene copolymer rubber), high-pressure low-density polyethylene resins, ethylene-ethyl acrylate copolymers, and ethylene-propylene copolymer rubber.
Examples include polyolefin resins such as vinyl acetate copolymers, polyamide resins, and saponified products of ethylene-vinyl acetate copolymers (ethylene-vinyl alcohol copolymers). Furthermore, in JP-A No. 62-25139, a high-pressure low-density polyethylene resin specified by the product of melt flow rate and melt tension and the melt flow rate and a density of 0.880 to 0.900 g/crr? It is a composition consisting of a copolymer of ethylene and α-olefin (linear ultra-low density polyethylene resin) and a polyethylene resin grafted with acrylic acid or maleic anhydride.It is a material with excellent moldability and adhesive properties. This is what we provide. Moreover, in JP-A-62-10107, good adhesion and
Density that combines heat sealability and heat resistance retention is 0.890 to 0.910g/crr? and a weight average molecular weight/number average molecular weight of 2 to 15, and a product of melt tension and melt flow rate at a temperature of 160°C of 4 or less and an a-olefin having 4 or more carbon atoms. A modified polyethylene resin as a copolymer and a composition of the modified polyethylene resin and an unmodified polyethylene resin have been proposed. Furthermore, JP-A-61-131345 and JP-A-61-1
No. 32377 has a density of 0.860 to 0.910 g.
/crn' and the boiling n-hexane insoluble content is 10
% by weight or more, and is measured using a differential scanning calorimeter (Diffe
rentalScanning Calorimet
er) 1 to 40 parts by weight of rubber per 100 parts by weight of a copolymer of ethylene and α-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. Graft-modified adhesive resins and laminates thereof have been proposed. Moreover, in Tokuko No. 60-36942, the degree of crystallinity is 4.
Graft modified product 9 of polyethylene resin with a content of 0% or more or polypropylene with a content insoluble in boiling n-hexane of 80% or more
Ethylene having a crystallinity of 9 to 50% by weight, a degree of crystallinity of 5 to 30%, and a density of 0.870 to 0.910 glcrd.
It is a multilayer laminate consisting of a polyolefin resin composition consisting of 1 to 50% by weight of an a-olefin copolymer and a nylon (polyamide resin) layer, and the interlayer adhesion, especially when immersed in boiling water, has been significantly improved. It is proposed to provide a laminate. However, the most preferred (crystallinity 5-30%, density 0.890-0.910g/
c) As an ethylene-α-olefin copolymer, the density when polymerized with a vanadium catalyst is 0.870 to
It mentions an ethylene-butene-1 random copolymer with a copolymerization rate of 0.900 g/crd, an ethylene copolymerization ratio of 85 to 95 mol%, and a crystallinity of 5 to 30%.

Problem to be Solved by the Invention J However, no matter which modified polyethylene resin or its composition is used, it is possible to achieve excellent fuel oil resistance (gasoline resistance) and impact resistance, which are the objectives of the present invention. It is extremely difficult to provide a material that has both affinity and adhesive properties. 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, these physical properties are used to improve the adhesion between polyamide resin layers and polyethylene resin layers used in multilayer polyethylene resin fuel containers (for example, three types and five layers), which are made of polyamide resin, with the aim of preventing the permeability of fuel oil such as gasoline. There are also strong demands on the layer, and the inventions proposed so far have not been able to sufficiently satisfy the requirements. In other words, ethylene-〇-olefin copolymer polymerized using a vanadium-based catalyst as a main catalyst or an elastomer such as synthetic rubber used in the production of graft-modified polyethylene resin or its composition to improve impact resistance, or an ethylene-〇-olefin copolymer with a density of 0 Graft-modified polyethylene resins or compositions thereof that are mainly composed of linear ultra-low-density polyethylene resins with .880 to 0.910 g/c rn' have extremely poor fuel oil resistance when used at high temperatures for long periods of time. Furthermore, even if, for example, a graft-modified high-density polyethylene resin alone or a composition of a graft-modified high-density polyethylene resin and an unmodified polyethylene resin or an unmodified low-density polyethylene resin can satisfy fuel oil resistance, It is difficult to obtain extremely good impact resistance, and it is also difficult to obtain good compatibility and adhesion with the various resin materials and metal materials. Further, taking the example of a large-sized molded product manufactured by blow molding, during normal molding, sludge is generated, and this sludge 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. However, the impact resistance of these barrier materials is significantly inferior to that of the relatively high molecular weight high-density polyethylene resin used for thermal blow molding, and the drawback is that their impact resistance is particularly poor 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 satisfy. Needless to say, in order to solve this problem, a new layer for recycling Paris (Paris layer) or an adhesive layer for bonding the main material (mainly polyethylene resin) and the barrier material is required. A method for recycling multilayer Paris has been proposed. However, the former is not economical as it requires new equipment, and the latter
PA in Paris (when PA is used as a barrier material)
is undesirable because it reacts with the graft-modified polyolefin resin, causing gelation and 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. 60-34461 (Japanese Unexamined Patent Application Publication No. 54-198) has been proposed.
113678) and Japanese Patent Publication No. 61-42625 (Japanese Unexamined Patent Publication No. 55-91634), it has been proposed to use polyolefin resins or polyamide resins that have specific adhesive properties. , the long-term fuel oil resistance of each resin is poor, making them 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). extremely excellent;
Furthermore, the objective is to obtain a material that has excellent affinity with materials to be recycled during recycling of paris generated during molding and has excellent adhesion to barrier materials such as polyamide resins. [Means and effects for solving the problems 1 According to the present invention, these problems are solved when +A) the density is 0,930g
/ crn' or more and melt flow rate)
A high-density polyethylene resin (measured under conditions 4 according to JIS K7210, hereinafter referred to as rMFRJ) of 0.01 g/10 minutes or more; Modified polyethylene resin grafted with at least one selected monomer and fCl The number of short chain branches per 1000 carbon atoms in the main chain is 18 to 60, and the density is 0.890 to 0.91.
0g/c IT1'', MFR (melt flow rate) is 0.1~30g/10min, and melting point by differential scanning calorimeter (DSC) method is 110~1
25°C, 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 The composition ratio of the linear ultra-low density polyethylene resin in the composition is 5.0 to 35% by weight, and the ratio of the crafted monomers in the entire composition is 0 as their total amount.
．． 001 to 5.0% by weight of a polyethylene resin composition. The present invention will be explained in detail below. (AJ 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 contain ethylene alone or ethylene and 3 to 12 carbon atoms (preferably , 3~
It is obtained by homopolymerizing or copolymerizing α-olefins (8) 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'' ( The α-olefin is preferably polymerized by a medium to low pressure method, such as propylene, butene-1,
Mention may be made of hexene-1,4-methylpentene-1 and octene-1. The copolymerization ratio is at most 6.5% by weight, preferably 6.0% by weight 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 0.930g/crd or more,
0.933g/crd or more is preferred, especially 0.933g/crd or more.
935 g/crr? The above is preferable. Density is 0.9
If a polyethylene resin of less than 30 g/crd is used, products molded using the resulting composition will be inferior in terms of rigidity, heat resistance, fuel oil resistance, surface hardness, etc. Furthermore, the MFR is 0.01 g/10 minutes or more, and the MFR is 0.01 g/10 minutes or more.
0.015g/10 minutes or more is desirable, especially 0.02g
/10 minutes or more is suitable. MFR is 0.01g/10
If it is less than 1 minute, moldability is not good. In addition, although the upper limit is not particularly limited, it is usually 50g/
10 minutes, particularly preferably 35 g/10 minutes or less. In particular, the modified polyethylene resin described below has an MFR of 0.
If it is less than 0.01 g/10 minutes, the M of the resulting grafted high-density polyethylene resin may vary depending on the graft modification conditions.
The FR is generally lower than the MFR of the high-density polyethylene resin used for grafting, resulting in lower moldability and significantly lower compatibility when producing a mixture with the non-grafted high-density polyethylene resin.
It is not possible to obtain a uniform composition. Therefore, the MFR of modified polyethylene resin is generally 0.05.
g/10 minutes or more is desirable, particularly 0.1 g/710 minutes or more. These high-density polyethylene resins may be used alone, or two or more types may be combined. The modified polyethylene resin used in 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 this. 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. (8) Unsaturated carboxylic acids and derivatives thereof The unsaturated carboxylic acids and derivatives thereof used in the kraft treatment in the present invention include -base unsaturated carboxylic acids and dibasic unsaturated carboxylic acids, and their metal salts, amides,
Imides, esters and anhydrides may be mentioned. Among these, the -base unsaturated carboxylic acid generally has at most 20 carbon atoms (preferably 15 or less). Also,
The number of carbon atoms in the derivative is usually at most 20 (preferably not more than is). 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-2,3-dicarboxylic acid and its anhydride, and glycidyl methacrylate are preferred, and maleic anhydride is particularly preferred. Acids and 5-norbornenic anhydride are preferred. IcI 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 1 minute half-life of 100°C or higher,
A temperature of 103°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(tert-butylperoxy)hexane, 2,5-dimethyl-2,5-di(tert-butylperoxy) ) Organic peroxides such as hexane-3, lauroyl peroxide, and tertiary-butyl peroxybenzoate can be mentioned. (D1 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 grafted 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, ethylene-ethyl Examples include copolymers of ethylene and other vinyl monomers such as acrylate copolymers, ethylene-butyl acrylate copolymers, and ethylene-methyl methacrylate copolymers. Also, examples of elastomers include ethylene-propylene copolymer rubbers. , ethylene-propylene-diene ternary copolymer rubber, ethylene-butene-1 copolymer rubber, etc.
α-olefin copolymer rubber, polyisobutylene rubber,
Polyurethane rubber, styrene-butadiene copolymer rubber,
Examples include synthetic rubber such as polybutadiene rubber and natural rubber. TE) Ratio In producing the graft-modified polyethylene resin of the present invention, the ratio of the unsaturated carboxylic acid and/or its derivative and the radical initiator to 100 parts by weight of the high-density polyethylene resin to be grafted is as follows. For unsaturated carboxylic acids and derivatives thereof, the total amount thereof is generally 0. O1 to 5.0 parts by weight, 0
．． O1 to 3.0 parts by weight is preferred, particularly 0.02 to 2.0 parts by weight.
0 parts by weight is preferred. The proportion of unsaturated carboxylic acids and their derivatives as their total amount is 0. If the amount is less than the original weight part, the graft modification will be insufficient and there will be a problem 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 gel, become colored, deteriorate, etc., and the performance improvement aimed at by the present invention will not be observed. Further, the ratio of the radical initiator is 1 usually o, oot to 1.
0 parts by weight, preferably from 0.005 to 1.0 parts by weight, and particularly preferably from o, oos to 0.5 parts by weight. If the proportion of the radical initiator is less than 0 parts by weight, the effect of graft modification will be poor, 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 1.0 parts by weight,
It is undesirable because it causes excessive decomposition or crosslinking reaction. Furthermore, when the synthetic resin or elastomer is used, the proportion thereof in the total amount with the high-density polyethylene resin is generally at most 10% by weight, and particularly preferably 5.0% 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. fF) 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 a radical-initiated It can be produced by processing the agent within the above-mentioned ratio range. The treatment method is as described in the specification of JP-A No. 62-10107, page 4, bottom left column, line 13 and onwards, and the specification of JP-A-61-132345, page 7, top left column, line 14 and onwards. A known method may be used. Processing methods include extruders, Banbury mixers,
A method in which high-density polyethylene resin is mixed in a molten state using a kneader, a solution method in which a polymer such as high-density polyethylene resin is dissolved in an appropriate solvent, and particles of a polymer such as high-density polyethylene resin. Examples include the slurry method, which is carried out in a suspended state, and the so-called gas phase grafting method. The treatment temperature is selected appropriately taking into account the deterioration of polymers such as high-density polyethylene resin, the decomposition of unsaturated carboxylic acids and their derivatives, the decomposition temperature of the radical initiator used, etc. For example, the temperature is usually 100-350℃, 150-300℃
is desirable, particularly 180 to 300°C. Of course, it is possible to produce the graft-modified high-density polyethylene resin of the present invention in this way by using already known treatment methods, such as graft modification, for the purpose of improving its performance. A method of treating with an epoxy compound or a polyfunctional compound containing an amino group or a hydroxyl group, etc. at the time or after graft modification;
Furthermore, a method of removing unreacted monomers (unsaturated carboxylic acids and derivatives thereof) and various by-product components by heating, washing, etc. can be adopted. (Gl Linear Ultra-Low Density Polyethylene Resin Also, the method for producing the linear ultra-low density polyethylene resin used in the present invention is widely known, and in recent years it has been improved by improving slurry polymerization method or gas phase polymerization method. It is industrially produced and widely used. Therefore, it is a product with a low crystallinity of several percent to about 30% that can be obtained by polymerization using a conventionally known vanadium catalyst system. Ethylene-α-olefin random copolymer (density 0.86-0.91 g/c
m'), for example, JP-A-57-6830
6, No. 59-23011, and No. 62-109805, which are manufactured by slurry method or gas phase method using stereoregular catalysts (so-called Ziegler catalysts). It is polyethylene resin. The linear ultra-low density polyethylene resin in the present invention has a density of 0.890 to 0.910 g/crd, M
F R is o, i ~ 30 g/10 min, and DSC
It is a linear low-density polyethylene resin having a melting point of 110 to 125° C. and a short chain branching number of 18 to 60 per 1000 carbon atoms in the main chain. In the present invention, the density of the polyethylene resin is 0.8
If it is less than 90 g/ctrl, there is a problem in the fuel oil resistance of the resulting composition.
If it exceeds ', the resulting composition will have insufficient impact resistance. From these facts, the density is 0.892 to 0.91
0 gZcrd is preferred. Further, if the MFR of the resin is less than 0.1 g 710 minutes, it is not preferable in terms of moldability and processability. On the other hand, if it exceeds 30 g/10 minutes, there is a problem in terms of impact resistance. From these things, MFR is O1~10g/10
Minutes are desirable, and 0.2 to 8.0 g710 minutes is particularly suitable. Furthermore, DSC (approximately 5B sample was manually prepared, and this was set in the DSC7j++ constant apparatus, and 20[1'C
After raising the temperature from room temperature at a rate of 10 °C/min to 10 °C/min, holding at that temperature for 5 minutes, then lowering the temperature to room temperature at a rate of 10 °C/min, and then raising the temperature at the above temperature increase rate. The melting point is defined as the peak temperature of the maximum endothermic region of 110 to 125°C. Particularly preferred is a temperature of 112 to 125°C. Melting point is 110℃
If it is lower than this, 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 50.
The number is preferably 20 to 50, particularly 20 to 50. If the number of short chain branches per 1000 carbon atoms in the main chain is less than 18, there is a problem 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. Here, the short chain is one consisting essentially of an alkyl group having 1 to 10 carbon atoms (preferably 1 to 6 carbon atoms). In addition, from the viewpoint of improving impact resistance, the initial tensile modulus of the polyethylene resin is 2 x 103 kgf/c.
rn” or less (preferably 1.5x 103kgf
/ crn" or less) is preferable. The polyethylene resin is obtained by copolymerizing ethylene and an α-olefin using a Ziegler catalyst. The α-olefin usually has 3 to 1 carbon atoms.
Two pieces (preferably 3 to 8 pieces) are desirable. Desirable α-olefins include propylene, butene-1,
Pentene-1, hexene-1,4-methylpentene-1
and octene-1. (Old composition ratio The composition ratio of the linear ultra-low density polyethylene resin in the polyethylene resin composition of the present invention is 5.0 to 35% by weight, preferably 5.0 to 33% by weight, particularly 7.0 to 35% by weight.
0 to 33% by weight is preferred. The composition ratio of the linear ultra-low density polyethylene resin in the polyethylene resin composition is 5.
If it is less than 0% by weight, the resulting composition will have poor impact resistance. On the other hand, if it exceeds 35% by weight, the fuel oil resistance (particularly the fuel oil resistance at 40° C.) is significantly reduced, which is not preferable. Further, 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, preferably 1.0% by weight or more, and particularly preferably 2.5% by weight. It is. If the composition ratio of high-density polyethylene resin and modified polyethylene resin is less than 0.1% by weight, the polyethylene resin composition that has sufficient affinity or adhesion with the resin materials, metal materials, etc., which is the object of the present invention, cannot be used. can't get it. fJ) Composition and method for producing the same In the polyethylene resin composition of the present invention, the high-density polyethylene resin, modified polyethylene resin, and linear very low-density polyethylene resin are each within the above-mentioned composition ratios. Generally, when graft-modifying a polymer (in the case of the present invention, a high-density polyethylene resin) with a monomer (in the case of the present invention, an unsaturated carboxylic acid or its derivative), it is difficult to graft the monomer to all the polymers. , there are polymers that are partially ungrafted. 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, the high-density polyethylene resin and the linear very low-density polyethylene resin may be mixed in advance, and the resulting mixture and the modified polyethylene resin may be mixed, or all the composition components may be mixed at the same time. In any of the above cases, the proportion of the grafted monomers in the polyethylene resin composition of the present invention is from o,oot to 5.0% by weight as a total amount thereof, and from 0.0% to 5.0% by weight.
Preferably 20% by weight, especially 0.02-1.0
% by weight is preferred. If the proportion of the grafted monomers in the polyethylene resin composition is less than 0.001% by weight in total, the various effects of the present invention cannot be fully exhibited. On the other hand, even if it exceeds 5.0% by weight, 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 melting and mixing 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 in which tri-blending is performed in advance and the resulting mixture is further melt mixed). fKl processing method The polyethylene resin composition of the present invention obtained in this way can be applied to containers such as industrial color and fuel oil tanks such as gasoline, and the hollow forming method which is generally practiced as a molding method thereof is used. It is possible to easily form it into a desired shape by using the method, and it is possible to obtain an article with unprecedented impact resistance. 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/B, A/C/B/C/A, A/C/B, A/C/B/C/A, and A/C/B, where A is the main material, B is the barrier material, and C is the composition of the present invention.
Three or more layers such as C/B/C, C/B/C/A (of course, a layer including a Paris layer generated during blow molding may be provided between the A and C layers in these structures) good)
It is. In addition, since the polyethylene resin composition of the present invention has affinity and adhesiveness with barrier resins such as PA, it can also be used as a C/B or C/B/C two-layer or two-layer structure based on barrier resins such as PA. It can be used as a laminate consisting of three layers. [Examples and Comparative Examples] The present invention will be explained in more detail with reference to Examples below. In addition, in the examples and comparative examples, the impact resistance is JIS
According to the K7110 method, the notched Izo impact strength was measured at temperatures of 23°C and -40°C using a press plate with a thickness of 3mm. In addition, the heat and fuel oil resistance (durability test) was determined by JI made from a press plate with a thickness of 2 cm.
After leaving the S No. 2 test piece in a gear oven at 115°C for 96 hours, it was placed in commercially available regular gasoline at 40°C for 20 hours.
After being immersed for 00 hours, the tensile elongation at break (El) was measured according to the JIS K7113 method, and evaluation was made by comparing with the tensile elongation at break (E,) of a specimen that was not subjected to the durability test. The modified polyethylene resin used in the Examples and Comparative Examples was manufactured as follows. MFR is 0.9 g/10 min and density is 0.9
52g/crr? Powdered high-density polyethylene resin (hereinafter referred to as rHDPEfilJ) containing 2.5-dimethyl-2,5 as a radical initiator to ioo parts by weight
0.012 parts by weight of -tertiary-butylperoxyhexane was added, and triblending was performed for 2 minutes using a Henschel mixer. Then, 0.35 parts by weight of maleic anhydride (hereinafter referred to as rMAHJ) as an unsaturated carboxylic acid or its derivative was added to the resulting mixture, and triblending was performed for 3 minutes using a Henschel mixer. The obtained mixture was extruded using an extrusion m (diameter 40■■),
It is melted and mixed at a resin temperature of 265°C and pelletized to produce modified polyethylene resin (hereinafter referred to as "modified PECAIJ").
It was created. The grafted M was measured by infrared absorption spectroscopy (hereinafter referred to as rIR method) of the modified P E [Al
The amount of AR was 0.31% by weight. The modified PE (HDP used in producing Al)
E (Instead of il, high-density polyethylene resin (hereinafter referred to as rHD P E fii) J having an MFR of 0.3 g710 min and a density of 0.955 g/crn' was used, except that modified P A modified polyethylene resin (hereinafter referred to as "modified PEfB") was produced by tri-blending and melt mixing in the same manner as in the case of Al. The amount was 0.29% by weight.Similarly, instead of the HDPE fil used in producing the modified PE(A), an MFR of 0.4 was used.
g/10 min and density is 0.935 g/c
rt? A modified polyethylene resin (hereinafter referred to as "modified PE (C)") was produced by tri-blending and melt mixing in the same manner as described above, except that the high-density polyethylene resin having the formula ' was used. The modified PE fcl was The amount of grafted MAH measured by IR method was 0.31% by weight.Furthermore, similarly, the modified P E (A)
HDP E (instead of IL) used in the production of
．． High density polyethylene resin 9 which is 958g/crn'
A random copolymer of ethylene and butene-1 with a density of 0.900 g/cni' and a butene-1 copolymerization ratio of 9.5 mol%. Modification of the polyethylene resin composition was carried out in the same manner as above except that a composition consisting of 5% by weight of the polymer was used! 9J (hereinafter “denatured P
E(D)J] was manufactured. The amount of grafted MAR in the modified PE (DJ) measured by IR method was 0.31% by weight.For comparison, the amount of grafted MAR in the modified PE (DJ) was 0.31% by weight. Tri-blending and melt mixing were carried out in the same manner as above, except that EBRC (ethylene-butene-1 random copolymer) described later was used instead of D P E (i), and modified polyethylene resin (hereinafter referred to as "modified EBRC") was used.
RCJ) was manufactured. The amount of grafted MAR measured by IR method on the modified EBRC was 0.30% by weight. Similarly, the HD used in producing the modified PE (A)
P E (i) was replaced with EPRC (ethylene-propylene random copolymer) described later, but tri-blending and melt mixing were performed in the same manner as above to produce a modified polyethylene resin (hereinafter referred to as "modified EPRCJ"). The amount of grafted MAH measured by the IR method of the modified EPRC was 0.29% by weight.Furthermore, as a high-density polyethylene resin, 1MFR was 0.29% by weight.
7g/10min, and the density is 0.952g/c
rrr' high-density polyethylene resin [hereinafter referred to as rHDP
E(I)J] and MFR is 0.06 g/10 min, and density is 0.944 g/crr? A high-density polyethylene resin rnDpE(II)J was used. In addition, as a linear ultra-low density polyethylene resin, the density obtained by polymerizing in a slurry state using a solid catalyst component containing titanium and a catalyst consisting of an organoaluminum compound system is 0.904 g/c rn'.
, the MFR is 1.0 g/10 min, the melting point (hereinafter referred to as m. p, J) by the rDSC method is 120°C, and the A linear ultra-low density polyethylene resin (hereinafter referred to as rLVLDPE(a)) having an average number of branches (hereinafter simply referred to as the “number of branches”) of 31.5.
, the density obtained by polymerization in a slurry state is 0.897 g/cm'', and the MFR is 0.76 g/1
0 minutes, and m and p are 113°C, and the number of branches is 43.
Furthermore, the density obtained by polymerizing by a solution method using the same catalyst as above was 0.908 g / c tr1
', MFR is 7.4 g/10 min, m, p, is 122 °C, and the number of branches is 24.4
Linear ultra-low density polyethylene resin [r L
V L D P E (I used J called cl J. For comparison, the density is 0.890 g/crr? and M
An ethylene-butene-1 random copolymer (hereinafter referred to as rEBRCJ) with a FR of 2.0 g/IO min, m, p, and 97°C, and a branching number of 67.5, and a density of 0. .923g/crn' and MFR is 0
．． 8 g/10 min, m, p, and 121'c, and the number of branches is 11. A linear ultra-low density polyethylene resin (hereinafter referred to as rLLDPEfelJ) has a density of 0.918 g/c rt? and MFR is 2.3
g/10 minutes, m, p, and 119°C, and the number of branches is 14.8. A linear ultra-low density polyethylene resin [hereinafter referred to as rLLDPFflJ, and a density of 0.894 g/c rr? and MFR is 0
．． An ethylene-propylene random copolymer (hereinafter referred to as rEPRCJ) having a weight of 8 g, 710 minutes, m and p of 42° C., and a branch number of 115 was used. Examples 1-15, Comparative Examples 1-12 Modified polyethylene resins, etc. 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) and linear ultra-low density polyethylene resin (hereinafter referred to as rL
VLDPEJ) was pre-triblended for 5 minutes using a Henschel mixer. Each mixture obtained was passed through an extruder equipped with a Dalmage screw (dia.
Pellet-shaped polyethylene resin compositions (the abbreviations of each composition are shown in Table 1) were produced by melt-kneading at a resin temperature of 190° C. using 501@). Test specimens were prepared from each of the obtained polyethylene resin compositions to measure Izot impact strength and heat resistance and fuel oil resistance, and the durability was evaluated as Izot impact strength and heat resistance and fuel oil resistance tests at temperatures of 23°C and -40°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. The results are shown in Table 2. (The following is a blank space) Table 2 (Part 1) Table 2 (Part 2) Example 16.17, Comparative Examples 13 to 15 Each polyethylene resin composition obtained in Examples 3 and 7 and Comparative Examples 2 and 3 Further, using the modified EBRC used in Comparative Example 10, two types and three layers of nylon 6 and three-layer sheets were cut into approximately 3III×6-w&tl: 8 sheets using a sheet cutter in the same manner as described below.
Part by weight and 92 parts by weight of the HDPE (II) with a diameter of 50 cm
A composition (bellet) consisting of 40% by weight of each composition and 60% by weight of HDPE (n) obtained by melt-kneading at a resin temperature of 260°C using a twin-screw co-directional extruder (2). Each was produced by melt-kneading at a resin temperature of 235° C. using a single-screw extruder with a diameter of 50 mm. The obtained pellets were pressed at a resin temperature of 230° C. to form an inner and outer layer, and a middle layer to form a sheet having a thickness of 2. The tensile elongation at break of each sheet obtained was measured in the same manner as described above for the evaluation of heat resistance and fuel oil resistance. In the case of only HDPE (n), the value was 800%, whereas in the case of using each composition obtained in Examples 3 and 7, the value was 825% and 810%, respectively. , 540% when using the compositions obtained in Comparative Examples 2 and 3, respectively.
and 740%. Moreover, when the modified EBRC used in Comparative Example 10 was used, it was 415%. In particular, the composition obtained in Comparative Example 2 and Comparative Example 1
When each of the modified EBRCs used in Example 0 was used, the tensile elongation at break not only significantly decreased, but also varied widely, and non-uniformity of elongation was observed during the tensile process. In order to evaluate the polyethylene resin composition of the present invention obtained as described above, the polyethylene resin compositions obtained in the reference examples and comparative examples described later were used as control examples, and the adhesiveness with polyamide resin was evaluated. The effects of the present invention will be clarified by comparison. [Reference and Control Examples] Adhesion was tested using a multilayer coextrusion device equipped with two extruders with diameters of 50 and 40Ill, respectively, and a multilayer T-die for two types and three layers. , trade name Amiran CM1046) was used in an extruder with a diameter of 40 m + m to form an intermediate layer with a thickness of 0.1 Onua, and a polyethylene resin composition prepared in the Examples or Comparative Examples with a diameter of 50 mm.
A two-type, three-layer sheet with inner and outer layers each having a thickness of 0.35+u+ was produced using an extruder at a molding temperature of 235°C. A peeling speed of 50 mm was measured using a tensilon type tensile tester at the interface of nylon 6 for each sheet sample obtained.
/min to perform T-type peeling to obtain the peeling resistance value (k
g/c+w width) was determined. Furthermore, as an evaluation of heat resistance and fuel oil resistance regarding adhesion, each multilayer section was left in an oven at 115°C for 96 hours, then immersed in commercially available regular gasoline at 40°C for 1000 hours, and then nylon 6 was immersed in the same way. The adhesion was determined after treatment. The results are shown in Table 3. (Margin below) Table 3 (Part 2) ◆・ Partial peeling between the eyebrows Table 3 (Part 1) Cutting of the middle sheet [Effect of the invention 1 The polyethylene resin composition of the present invention exhibits the following effects. . fl) It not only has excellent impact resistance at room temperature, but also good impact resistance at low temperatures (for example, -40°C). (2) Excellent heat resistance and fuel oil resistance. (3) Polyethylene resin, polyamide resin, EVOH1
It has good affinity and adhesion with various resin materials such as thermoplastic polyester resins and various metals, and in particular, it is also possible to create laminates in which the composition of the present invention is interposed between polyethylene resin and polyamide resin. can. 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. +11 Gasoline tanks and other parts. (2) Various packaging materials. (3) Various industrial materials. Various procedural amendments using fuel oil (voluntary)

Claims (1)

[Scope of Claims] (A) A high-density polyethylene resin having a density of 0.930 g/cm^3 or more and a melt flow rate of 0.01 g/10 minutes or more, (B) The high-density polyethylene resin A modified polyethylene resin grafted with at least one monomer selected from the group consisting of unsaturated carboxylic acids and derivatives thereof, and (C) a short chain branching number of 1 per 1000 carbon atoms in the main chain.
8 to 60 pieces, and the density is 0.890 to 0.910
g/cm^3, and the melt flow rate is 0.1 to 3.
0 g/10 min, and has a melting point of 110 to 125°C as measured by differential scanning calorimetry. The composition ratio of the modified polyethylene resin is at least 0.1% by weight, and the composition ratio of the linear ultra-low density polyethylene resin in the entire composition is 5.0 to 35% by weight, and The proportion of the grafted monomers in the polyethylene resin composition is 0.001 to 5.0% by weight based on their total amount.