JPH04198206A - Modified polymer and its production - Google Patents

Abstract

PURPOSE:To obtain a modified polymer having high adhesion to metals, glass and polar resins at a high grafting ratio by cografting ethylene and an unsaturated carboxylic acid onto a particulate polyolefin at a temperature below the crystalline melting temperature in a specified solvent in the presence of a radical reaction initiator. CONSTITUTION:Ethylene and an unsaturated carboxylic acid (salt or ester) are cografted onto a particulate polyolefin (e.g. polypropylene of a mean particle diameter of 700mum or below) at a temperature below the melting point of the polyolefin in the presence of a radical polymerization initiator in a swellable solvent having a low chain transfer constant (e.g. aliphatic or aromatic hydrocarbon) to obtain a modified polymer having a grafting ratio of 1.2wt.% or above for the unsaturated carboxylic acid and 0.1wt.% or above for the ethylene and an MFR 0.5-30 times as high a that of the starting polyolefin. Maleic anhydride or the like is used as the unsaturated carboxylic acid in such an amount or to give a molar ratio thereof to the ethylenically unsaturated carboxylic acid of 0.3-5.0, and the amount of the solvent is 20-150 pts.wt. per 100 pts.wt. polyolefin.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method for producing a novel modified polymer.

More specifically, the modified polymer may be used as it is or in the form of a modified polymer composition obtained by blending the modified polymer with a polyolefin, as a polyolefin, polyethylene terecrate, polystyrene or nylon, or a portion of an ethylene-vinyl acetate copolymer. It can be laminated with oxygen barrier resins such as saponified materials (hereinafter abbreviated as EVOH), metal plates or metal foil paper, and used as a reinforcing layer for multilayer laminates or as an adhesive layer for laminates of these base materials. It is used in food packaging materials, industrial packaging materials, and automobile materials.

[Prior Art] Conventionally, polyolefin is an excellent material that is inexpensive and has good mechanical properties, moldability, etc.
On the other hand, it not only lacks gas barrier properties, fragrance retention properties, and light blocking properties, but also has the drawback of poor adhesion to metals, glass, and polar resins such as nylon and EVOH.

In order to compensate for these drawbacks, there are methods in which polar molecules such as acrylic acid, maleic acid, maleic anhydride, and methyl acrylate are melt-grafted onto polyolefin using a radical initiator using an extruder, or polyolefin is melt-grafted using an extruder. Polyolefin modification methods have been proposed, such as a method in which grafting is carried out in a solution state, but none of these methods has yielded a modified polyolefin with a high grafting rate.

In addition, a method of grafting a polar monomer such as maleic anhydride alone without dissolving or melting powdery polyolefin in a substantially solvent-free manner (Japanese Unexamined Patent Publication No. 5O-7749
Although 3) has been proposed, the grafting ratio of the polar monomer to the polyolefin is low and sufficient adhesion is not obtained.

Further, in the presence of an inert gas, in substantially no solvent, unsaturated carboxylic acids such as maleic anhydride and maleimide, and derivatives thereof, and propylene, ethylene, etc. having 2 to 5 carbon atoms,
There has also been a proposal for a method of co-grafting with an olefin (Japanese Patent Application Laid-Open No. 64-87641) or an unsaturated silane compound such as vinyltrimethoxysilane (Japanese Patent Application Laid-open No. 1-108207). In this case, the grafting ratio to the polyolefin is has been reported to be high. However, in this method, the monomer is grafted non-uniformly onto the polyolefin, so it is thought that the mobility of the grafted chains that exhibit adhesiveness, particularly the mobility of the grafted unsaturated carboxylic acid or its derivative group, is reduced. However, the adhesion is so low that it cannot be used practically. Furthermore, a method has been proposed in which an a-olefin having 2 to 4 carbon atoms and an unsaturated carboxylic acid anhydride are polymerized in the presence of a polyolefin (Japanese Patent Publication No. 62-4050), but this method uses a large amount of solvent, - The grafting rate of the alternating copolymer of olefin and unsaturated carboxylic acid anhydride to polyolefin is low.

[Problems to be Solved by the Invention] The present invention began research with the aim of producing a modified polymer with a high grafting rate and high adhesiveness to metals, glass, and polar resins. In this case, recent trends in usage, cost, ease of reaction control, etc. are naturally taken into consideration.

For example, recently, considering the case of coatings using powdered polymers or blends of other resins and organic or inorganic fillers, the conventional melt grafting method or solution grafting method requires a powdering step after the reaction is completed, a polymer solution is This was done in consideration of the need to omit the solvent recovery step that was required from It was done.

[Means for Solving the Problems] In order to obtain a modified polymer having excellent adhesion to metal, glass, EVOH, nylonized polar resin, etc., the present inventors added the polyolefin to powdery polyolefin. At a temperature lower than the melting temperature of the crystal, using a radical reaction initiator, unsaturated carboxylic acids or derivatives thereof (hereinafter both are collectively referred to as unsaturated carboxylic acids, etc.)
) with ethylene, the amount of a solvent with low chain transfer properties that can swell the polyolefin is 20 to 150 parts by weight per 100 parts by weight of the polyolefin. It has been found that the above-mentioned problem can be solved by allowing i parts to coexist, and the present invention has been completed.

In the present invention, polyolefins are homopolymers of olefins such as ethylene, propylene, 1-butene, 3-methyl-butene-1,1-hexene, 4-methyl-pentene-1,1-octene, or Random or block copolymers of two or more olefins, or copolymerization of these olefins with at least one of vinyl acetate, acrylic acid, methacrylic acid, acrylic acid alkyl esters, methacrylic acid alkyl esters, etc. It refers to copolymers and modified products thereof, and also includes mixtures thereof.

Specifically, for example, high density polyethylene, low density polyethylene, linear low density polyethylene, polypropylene,
Ethylene-propylene random copolymer, ethylene-propylene rubber, ethylene-butene-1 rubber, ethylene-
Propylene-1-butene random copolymer, ethylene-
Propylene block copolymer, ethylene-propylene-
1-butene block copolymer, ethylene-vinyl acetate copolymer, propylene-1-butene random copolymer, ethylene-acrylic acid copolymer, metal salt of ethylene-methacrylic acid copolymer, ethylene-methyl methacrylate copolymers, ethylene-ethyl acrylate copolymers, etc.

As the radical reaction initiator, compounds that generate free radicals, mainly organic peroxides, are used. For example, dialkyl peroxides such as dialkyl peroxide, dicumyl peroxide, t-butylcumyl peroxide,
Diacyl peroxides such as acetyl peroxide, i-butyryl peroxide, octanoyl peroxide, lauroyl peroxide, benzoyl peroxide, 0-methylbenzoyl peroxide, di]-propyl peroxydicarbonate, di-2-ethylhexyl peroxide, etc. Peroxydicarbonates such as oxydicarbonate, peroxyesters such as t-butyl peroxybivalate and t-butyl peroxylaurate, ketone peroxides such as methyl ethyl ketone peroxide and cyclohexanone peroxide, 1,1-bis - Peroxyketals such as t-butylperoxycyclohexane and 2.2-bis-t-butylperoxyoctane, hydroperoxides such as t-butyl hydroperoxide and cumene hydroperoxide, 2.2-azobisiso Examples include azo compounds such as butyronitrile, oxygen, etc., but benzoyl peroxide and di-i-propyl peroxydicarbonate are preferred from the viewpoint of crosslinking efficiency, half-life temperature, etc. The amount of the radical reaction initiator used is usually 0.1 to 30 parts by weight, preferably 3 to 12 parts by weight, per 100 parts by weight of the polyolefin. If the amount of the radical reaction initiator is less than 0.1 part by weight, the grafting rate will be low and sufficient adhesiveness will not be obtained. If it exceeds 30 parts by weight, many side reactions such as decomposition and crosslinking will occur, resulting in a decrease in MFR.
changes significantly compared to the polyolefin before modification, causing difficulties in molding processability. In order to exhibit sufficiently stable performance, it is preferable to use 3 to 12 parts by weight.

In the present invention, unsaturated carboxylic acids, etc. refer to maleic anhydride, maleic acid, maleic acid dialkyl esters, and N-
These include alkyl- and phenyl-substituted maleimides, maleimides, and the like. Preferred are maleic anhydride and maleimide.
- The amount of unsaturated carboxylic acid, etc. to be used varies depending on the properties of the target modified polymer and cannot be generalized, but it is usually 3 to 50 parts by weight, preferably 4 to 50 parts by weight, based on 100 parts by weight of polyolefin. ~20 parts by weight. If the amount of the unsaturated carboxylic acid used is lower than 3 parts by weight, the grafting rate will decrease and sufficient adhesiveness will not be obtained.

If the amount exceeds 50 parts by weight, the grafting rate will become too high and the resulting modified polymer will lose its polyolefin properties, especially good processability, and the grafting rate will decrease.
For example, if conditions are adopted such as reducing the amount of radical reaction initiator used or lowering the molar ratio of ethylene/unsaturated carboxylic acid, etc., the amount of unreacted substances will increase, so the cleaning step after the co-grafting reaction will not be necessary. The amount of solvent used increases,
This would be extremely disadvantageous in terms of cost in terms of industrial production.

It is essential that the co-grafting reaction be carried out in the presence of ethylene and unsaturated carboxylic acid. The amount of ethylene gas is usually determined by the molar ratio (ethylene/
The molar ratio of unsaturated carboxylic acids, etc.) is from 0.3 to 5.0, preferably from 0.4 to 2.0. If the molar ratio of ethylene gas to unsaturated carboxylic acid or the like is lower than 0.3, the grafting ratio will be low, and if it exceeds 5.0, the melt flowability will be greatly reduced, which is a problem in molding processing.

The co-kraft method is preferably a method in which kraft polymerization is performed in a state where the powdery polyolefin is not dissolved or melted. In more detail, 2 shows that it is preferable to carry out the cografting at a temperature lower than the peak temperature of the melting point of the polyolefin (both 30°C lower). It is preferable to conduct the reaction within the range of 30°C. If the temperature exceeds 30°C below the peak melting point of the polyolefin, partial melting of the polyolefin will be observed, and a large amount of modified polymer will adhere to the walls of the reaction vessel after co-grafting. This is disadvantageous in industrial production at the post-treatment stage.If the peak temperature is lower than 100°C, the co-grafting rate will decrease, and the melt flowability of the modified polymer will decrease significantly, making it difficult to maintain sufficient adhesion. Molding processability cannot be obtained.

Although the reaction time cannot be absolutely defined depending on the decomposition temperature of the radical reaction initiator used, it is usually about 0.5 to 5 hours. Further, -1: It is necessary from the viewpoint of grafting efficiency and cost that at least 90% or more of the radical reaction initiator used becomes a radical species.

The shape of the polyolefin used needs to be in the form of powder particles for the efficiency of grafting, and it is further preferable that the average particle size is at most 700 μm; if the particle size is larger than 700 μm, the efficiency of grafting will decrease.

The co-craft reaction is carried out in the presence of a low chain transfer solvent that can swell the polyolefin.

The solvent swells the powdered polyolefin and contains ethylene,
Since unsaturated carboxylic acids, radical reaction initiators, etc. can easily penetrate into the interior of the polyolefin particles, the polyolefin can be more uniformly co-graft modified.

Specific examples of such solvents include saturated hydrocarbons such as isobutane, pentane, hexane, cyclohexane, and octane, and aromatic hydrocarbons such as benzene, toluene, and xylene.

The amount of the solvent used is usually 20 to 150 parts by weight, preferably 30 to 12 parts by weight, per 100 parts by weight of the polyolefin.
It is 0 parts by weight. If the amount of the solvent used is less than 20 parts by weight, the swelling of the particulate polyolefin will not be sufficient, resulting in a modified polymer that has a high grafting rate but cannot obtain sufficient adhesiveness.

Furthermore, if the amount of solvent used exceeds 150 parts by weight, the monomer' concentration decreases and the grafting rate decreases, making it impossible to obtain sufficient adhesion.Furthermore, partial dissolution of the powdery polyolefin is observed, resulting in After grafting, the shape of the polyolefin changes, which is disadvantageous in industrial production at the post-treatment stage.

After the co-grafting reaction, the modified polymer undergoes a step to remove unreacted unsaturated carboxylic acids, radical reaction initiators, and reaction by-products for the purpose of improving adhesion, preventing coloration, and removing corrosiveness and toxicity. attached to.

Possible methods include washing by extraction or dissolution and reprecipitation using a solvent, or sublimation and scattering by reduced pressure and heating.

The obtained modified polymer contains unreacted unsaturated carboxylic acids, etc.
Or reaction by-products are purified to a residual state of at most 700 ppm or less. If the content exceeds 700 ppm, adhesive properties may deteriorate.

In addition, modified polymers that exhibit sufficient adhesion must have a grafting amount of unsaturated carboxylic acid, etc. of 1.2% by weight or more, a grafting amount of ethylene of 0.1% or more, and a MFR (JIS K
7210 (2.16 kg load) must be in the range of 0.5 to 30 times that before the co-craft reaction. If the grafting amount of each component is less than the above-mentioned amount or if the MFR is outside the above-mentioned range, sufficient adhesion cannot be obtained.

The modified polymer obtained here can be used as it is or in the form of a modified polymer composition obtained by blending the modified polymer with the polyolefin, such as polyolefin, oxygen barrier resin such as nylon or EVOH, metal foil, paper, etc. It can be used as a reinforcing layer or an adhesive layer in multilayer laminates.

If a modified polymer is used alone, the moldability will deteriorate somewhat and the cost will increase, so it is usually preferable to use a blended product with a polyolefin.

The blend ratio of the modified polymer and the polyolefin is:
The content of unsaturated carboxylic acid, etc. in the modified polymer composition is 0.12% by weight or more, and the content of grafted ethylene is 0.
．． The blend ratio is preferably 0.01% by weight or more, and if the blend ratio is less than the above range, sufficient performance cannot be obtained.

This modified polymer has extremely good affinity with polyolefins,
Furthermore, since it has a certain degree of affinity with other polar polymers, it can also be used as a compatibilizer for polymer alloys of polyolefins and resins with low affinity for polyolefins. It is also possible to use glass, metal, carbon fiber, inorganic fiber, inorganic filler and the modified polymer or modified polymer composition as a composite molded body.

Five well-known additives and compounding agents may be added to the modified polymer and modified polymer composition depending on the intended use of the composition. Examples of additives and compounding agents include antioxidants (heat stabilizers), ultraviolet absorbers (light stabilizers), antistatic agents, antifogging agents, flame retardants, and lubricants (slip agents, antiblocking agents).
, inorganic and organic fillers, reinforcing materials, colorants (dyes, pigments), blowing agents, crosslinking agents, perfumes, etc.

Examples of heat-resistant stabilizers include phenolic stabilizers, sulfur-based stabilizers, and phosphorus-based stabilizers. Specifically, for example, 2,6-di-t-butyl-4-methylphenol , phenolic stabilizers such as stearyl-β-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, sulfur stabilizers such as dilaurylthiodipropionate, distearylthiodipropionate, tris. (nonylphenyl) phosphite, distearylpentaerythritol diphosphite, tetra(tridecyl)-1,1,3-tris(2-methyl-5-t-butyl-4-hydroxyphenyl)butane diphosphite, etc. May represent a system stabilizer.

Examples of light stabilizers include salicylic acid-based, benzophenone-based, and benzotriazole-based stabilizers, and specific examples include salicylic acid-based stabilizers such as phenyl salicylate and p-octylsalicylate; - benzophenone stabilizers such as dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2- (2'
-Hydroxy-5'-methylphenyl)benzotriazole, benzotriazole stabilizers such as 2-(2°-hydroxy-4°-n-octyloxyphenyl)benzotriazole, resorcinol monobenzoate, and the like.

Antistatic agents and antifogging agents include esters such as pentaerythritol monostearate, glycerin monostearate, and glycerin distearate.

Sulfates such as lauryl soda sulfate and lauryl chlorosulfonate, phosphorus oxides such as dioleyl phosphate and dioleyl phosphate, amides such as N,N-dimethyl-acetic acid soda oleic acid amide, lauryl trimethyl ammonium chloride, lauryl dimethyl benzyl ammonium chloride, etc. Quaternary ammonium salt of stearyl dimethyl betaine,
Examples include betaines such as lauryldihydroxybetaine and lauryldimethylsulfobetaine, and polyethylene glycol type nonionic antistatic agents.

Flame retardants include chlorinated paraffin, chlorinated polyethylene, chlorentic anhydride, tetrabrominated bisphenol A,
Halogenated flame retardants such as tetrabrominated phthalic anhydride, dibromodichloropropane, trischloroethyl phosphate,
Examples include phosphate ester flame retardants such as bischloropropyl chloroethyl phosphate, and non-halogen flame retardants such as antimony oxide and magnesium hydroxide.

Examples of lubricants (including slip agents, anti-blocking agents, etc. in a broad sense) include hydrocarbon-based, fatty acid-based, fatty acid amide-based, ester-based, fatty acid lower alcohol ester, alcohol-based compounds or mixtures, and lubricants such as metal soaps. can be mentioned.

Examples of fillers include carbon black, white carbon, calcium carbonate, hydrous basic magnesium carbonate,
Clay, silicate minerals, natural silicic acid, alumina hydrate, barium sulfate, calcium sulfate, metal powder, organic fillers (e.g. wood flour, fruit flour, cellulose, etc.), etc., as reinforcing materials such as asbestos, Glass fibers, carbon fibers, stainless steel fibers, aluminum fibers, potassium titanate fibers, aramid fibers, glass peas, aluminum flakes, etc. may be mentioned.

As a crosslinking agent, the various peroxides mentioned above can be used as a radical polymerization initiator, and as a crosslinking aid, for example, lauryl methacrylate, ethylene glycol dimethacrylate,
Methacrylate compounds such as trimethylolpropene trimethacrylate, allyl compounds such as diallyl fumarate, diallyl phthalate, triallyl isocyanurate, quinone dioxime compounds such as p-quinone dioxime, dibenzoylquinone dioxime, Alternatively, the crosslinking efficiency can also be increased by using a compound such as divinylbenzene, vinyltoluene, 1.2 polybucdiene, etc. 6 Melt flow rate Examples and comparative examples are shown below.
MFR) is JIS K 7210 (2゜16k
g load); add 1. Quantification of unsaturated carboxylic acids, etc. and ethylene was carried out using CNMR and infrared absorption spectroscopy.

(Example 1) In an autoclave with an internal volume of 0.5 L, polypropylene powder (MFR, (230°C) 22 g/10 minutes average particle size 2
50g of 50tim), 6.0g of maleic anhydride, 3.0g of benzoyl peroxide and 25g of benzene were added, and after purging with nitrogen, 1.7g of ethylene was fed and the mixture was heated at 30°C.
6 After stirring for 0 minutes, the temperature was immediately raised to 100°C, and 3
The graft reaction was carried out simultaneously. After the reaction was completed, the mixture was washed five times with 300 ml of acetone at 30'C, and then dried under reduced pressure. The MFR (230°C) of the obtained modified polymer was 90.
At 8 g/10 min, 2.51 wt% maleic anhydride and 1.12 wt% ethylene were cografted onto the modified polymer.
%Met.

Further, the amount of remaining unreacted substances was 180 pPm, and the amount of reaction by-products was 170 ppm.

(Example 2) The same procedure as in Example 1 was conducted except that hexane was used instead of benzene.

The MFR (230°C) of the obtained modified polymer was 124 g/
At 10 minutes, 2.13 wt% maleic anhydride and 0.91 wt% ethylene were cografted onto the modified polymer. Further, the amount of remaining unreacted substances was 190 ppm, and the amount of reaction by-products was 150 ppm.

(Example 3) The same procedure as in Example 1 was conducted except that 6.0 g of maleimide was used instead of 6.0 g of maleic anhydride. MFR of the obtained modified polymer (230°C)
was 51.4 g/10 min, maleimide cografted to the modified polymer was 2.31 wt%, and ethylene was 0.89 wt%.
It was wt%. In addition, the remaining unreacted material was 70 ppm.
, reaction by-products were 540 ppm.

(Example 4) Instead of 50 g of polypropylene powder, 50 g of high-density polyethylene powder (MFR (190 ° C. 118 g / I
0 minutes Density 0.958 g/cm” Average particle size 320
The same procedure as in Example 1 was carried out except that the cografting temperature was 90° C. and the cografting time was 4 hours. The MFR (190°C) of the obtained modified polymer was 27.
At 9 g/10 min, 2.56 wt % maleic anhydride and 1.09 wt % ethylene were cografted onto the modified polymer.
%Met. In addition, the remaining unreacted substances were 210 ppm,
The reaction by-product was 250 ppm.

(Example 5) Instead of 50 g of polypropylene powder, 50 g of linear low density polyethylene powder (MFR (190°C) 20 g/lo
Minutes, degree of heat 0, 918 g/cm' average particle size 250μ
The same procedure as in Example 2 was carried out except that m) was used, the initiator was di-l-probilver, and the co-craft temperature was 70°C. MFR of the obtained modified polymer
(190°C) was 20.1 g/10 minutes, maleic anhydride co-grafted to the modified polymer was 2.58 wt%, and ethylene was 1.17 wt%. Further, the amount of remaining unreacted substances was 190 ppm, and the amount of reaction by-products was 280 ppm.

(Example 6) Instead of 50 g of polypropylene powder, 50 g of ethylene-propylene random copolymer powder (MFR (230 ° C.
) 17 g/l, 0 min, ethylene content 5.2 wt%, average particle size 340 μm), co-grafting temperature 90°C,
The same procedure as Example I was carried out except that the cografting time was 4 hours.

The MFR (230°C) of the obtained modified polymer is 40.1g
/10 minutes, maleic anhydride cografted to the modified polymer was 2.46 wt%, ethylene was 1.06 wt%, remaining unreacted material was 240 ppm, reaction by-product was 190 ppm. there were.

(Example 7) The same procedure as in Example 1 was conducted except that the amount of ethylene feed was changed to 0.8 g. MFR of the obtained modified polymer (230
°C) was 165 g/10 min, maleic anhydride cografted to the modified polymer was 1.52 wt%, and ethylene was 0.
．． It was 64 wt%.

Further, the amount of remaining unreacted substances was 210 ppm, and the amount of reaction by-products was 190 ppm.

(Example 8) The same procedure as Example 1 was carried out except that 1.5 g of benzoyl peroxide was used. MFR (23
0° C.) was 27.3 g/10 min, maleic anhydride co-grafted to the modified polymer was 1.82 wt%, and ethylene was 0.69 wt%. Further, the amount of remaining unreacted substances was 390 ppm, and the amount of reaction by-products was 1100 ppm.

(Example 9) The same procedure as Example 2 was carried out except that 50 g of hexane was used.

The MFR (230°C) of the obtained modified polymer was 184 g/
At 10 minutes, 1.41 wt% maleic anhydride and 0.57 wt% ethylene were cografted onto the modified polymer. Further, the amount of remaining unreacted substances was 410 ppm, and the amount of reaction by-products was 90 pPm.

(Comparative Example 1) The same procedure as in Example 1 was carried out except that ethylene was not used. The MFR (230°C) of the obtained modified polymer was 320 g/
At 10 minutes, the maleic anhydride grafted onto the modified polymer was O, 18 wt%.

Further, the amount of remaining unreacted substances was 510 ppm, and the amount of reaction by-products was 90 ppm.

(Comparative Example 2) The same procedure as in Example 1 was carried out except that 3 g of benzene was used. The MFR (230°C) of the obtained modified polymer was 3.1
g/10 min, 1.5'1 wt% maleic anhydride and 0.62 wt% ethylene cografted onto the modified polymer.
%Met. In addition, the remaining unreacted substances were 170 ppm,
The reaction by-product was 330 ppm.

(Comparative Example 3) The same procedure as in Example 2 was carried out except that 200 g of hexane was used. The MFR (230°C) of the obtained modified polymer was 50.2 g 710 minutes, maleic anhydride co-grafted to the modified polymer was 0°18 wt%, and ethylene was 0.0
It was 8wt%. In addition, the remaining unreacted material is 390p
pm, reaction by-products were 50 ppm.

(Comparative Example 4) Example 1 except that 40 g of tetrahydrofuran was used.
I did the same thing. MFR of the obtained modified polymer (23
0° C.) was 62.1 g/10 min, maleic anhydride co-grafted to the modified polymer was 0.32 wt%, and ethylene was 0.15 wt%. Further, the amount of remaining unreacted substances was 320 ppm, and the amount of reaction by-products was 90 ppm.

(Comparative Example 5) The same procedure as in Example 1 was carried out except that maleic anhydride was changed to 1.0 g, ethylene was changed to 0.3 g, and benzoyl peroxide was changed to 2.0 g. The MFR (230°C) of the obtained modified polymer was 39.2 g/10 min, maleic anhydride co-grafted to the modified polymer was 0.29 wt%, and ethylene was 0.1 wt%.
It was 2wt%. In addition, the remaining unreacted material is 380p
pm, reaction by-products were 50 ppm.

(Comparative Example 6) The same procedure as in Example 1 was conducted except that the amount of ethylene fed was 14 g. MFR of the obtained modified polymer (230
°C) was 4.1 g for 710 min, maleic anhydride co-grafted to the modified polymer was 2.94 wt%, and ethylene was 1
．． It was 31 wt%. In addition, the remaining unreacted substances are 11
00 ppm, and reaction by-products were 530 ppm.

The results of the above Examples 1 to 9 and Comparative Examples 1 to 6 are summarized in Table 1.

(Reference Example) The modified polymers obtained in Examples] to 9 and Comparative Examples 1 to 6 were mixed with polypropylene (MFR (230°C) 5.5 g/jO
), high density polyethylene (VFR (190°C) 6.2
g/10 min, density 0.954 g/amj), linear low density polyethylene (MFR (190°C) 4.8 g/
10 minutes Density: 0.915 g/cm”) Ethylene-propylene copolymer (MFR (230°C) 4.3 g/10 minutes
A modified polymer composition having a polymer content of 10 to 40% by weight was obtained by blending with a resin selected from a density of 0.883 g/c+e'').

The modified polymer composition and EVOH (ethylene-containing m:
32 mol%) to 40mm! , 45 mm $ 0) Using a two-type, two-layer coextrusion multilayer T-die film forming machine, a two-type, two-layer film (each layer thickness: 30 μm) was formed using a chill roll with water flowing at a die temperature of 220°C. . The obtained laminate film was subjected to a 180° peel test at a peel rate of 3.
Evaluation was made at 00mm for 7 minutes. The results are shown in Table 2.

From the above results, the modified polymer modified by the method of the present invention has excellent compatibility with polyolefin, and even the polymer composition blended with polyolefin has an EV
It can be seen that it exhibits high adhesive strength with OH.

[Effects of the Invention] For the powdery polyolefin of the present invention, 20 to 150 parts by weight of a hot medium that can swell the polyolefin is added to the powdery polyolefin. The co-grafted modified polymer can greatly improve performance such as adhesion, printability, and paintability.

Further, the modified polymer can be mixed with the above-mentioned polyolefin and used as a resin composition having the above-mentioned performance.

Claims (4)

[Claims] (1) When co-grafting an unsaturated carboxylic acid or a derivative thereof onto a powdery polyolefin in the presence of ethylene using a radical reaction initiator at a temperature lower than the melting temperature of the polyolefin crystal, the polyolefin is swollen. A method for producing a modified polymer, characterized in that 20 to 150 parts by weight of a solvent with low chain transfer properties is allowed to coexist with respect to 100 parts by weight of the polyolefin. (2) Claim 1, wherein the unsaturated carboxylic acid or its derivative is at least one compound selected from maleic anhydride, maleic acid, maleic acid dialkyl ester, N-alkyl, phenyl-substituted maleimide, and maleimide. A method for producing a modified polymer. (3) 0.1 to 30 parts by weight of a radical reaction initiator, 3 to 50 parts by weight of an unsaturated carboxylic acid or its derivative, and ethylene/
The molar ratio of unsaturated carboxylic acid or its derivative is 0.3
5.0 to 5.0. (4) The modified polymer has an unsaturated carboxylic acid or its derivative grafted amount of at least 1.2% by weight, an ethylene grafted amount of at least 0.1% by weight, and an MFR of from 0.5 to 0.5% based on the powdery polyolefin. A method for producing a modified polymer according to claim 1, in which the amount is increased by 30 times.