JPH04189809A - Preparation of modified polymer - Google Patents

Abstract

PURPOSE:To prepare a modified polymer having good adhesivity, printability and coatability and useful for packaging materials etc., by co-grafting ethylene and an unsaturated carboxylic acid to a powdery particulate polyolefin in the presence of a continuously or dividedly fed radical initiator at a low temperature. CONSTITUTION:When an unsaturated carboxylic acid or a derivative thereof (e.g. maleic anhydride) is grafted to a powdery particulate polyolefin in the presence of a radical initiator and ethylene at a temperature lower than the melting point of the polyolefin to prepare the objective modified polymer, 100 pts.wt. of the polyolefin, 2-30 pts.wt. of the unsaturated carboxylic acid or a derivative thereof in an ethylene/unsaturated carboxylic acid (derivative) molar ratio of 0.3-5.0. and 0.1-20 pts.wt. of the radical reaction initiator are employed, the radical reaction initiator being fed into the reaction system continuously or in at least three portions.

Description

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

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

[Prior art] Conventional polyolefins are inexpensive, have good mechanical properties,
Although this material has excellent moldability, it lacks gas barrier properties, fragrance retention properties, and light blocking properties (it has poor adhesion to metals, glass, and barrier substances such as nylon and EVOH). There are drawbacks.

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 polyolefins using a radical initiator using an extruder, or polyolefins are melt-grafted using an extruder or the like. Polyolefin modification methods have been proposed, such as a method of dissolving and grafting 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 the powdery polyolefin in a substantially solvent-free manner (Japanese Unexamined Patent Publication No. 50-7749
Although No. 31 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, unsaturated carboxylic acids such as maleic anhydride and maleimide and their derivatives, olefins having 2 to 5 carbon atoms such as propylene and ethylene (Japanese Unexamined Patent Application Publication No. 64-87611), and vinyltrimethoxy There has also been a proposal for a method of co-grafting monomers of unsaturated silane compounds such as silane (Japanese Unexamined Patent Publication No. 1-108207). has been reported to be high. However, in this method, since the above-mentioned polymers are grafted non-uniformly to the polyolefin, the mobility of the grafted chains that exhibit adhesiveness, in other words, the mobility of the grafted unsaturated carboxylic acid or its derivative group is affected. It is thought that the adhesion properties are low and cannot be used practically.

In addition, if ethylene and maleic anhydride, which do not have very high alternating copolymerizability, are co-grafted by adding a radical initiator to the system first,
A large amount of radicals are generated non-uniformly, and as a result, the obtained modified polymer has partial gelation, which is unfavorable in terms of molding process. Sufficient adhesion was not obtained due to the decrease in the grafting rate.

[Problem to be Solved by the Invention 1] 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 account.

For example, 2. Recently, in consideration 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, This was done in consideration of omitting the step of recovering the solvent from the solution, which was necessary, and the method of the present invention almost achieves the main objectives of the method, which are a high grafting rate and an improvement in adhesion. achieved.

[Means for Solving the Problems J] In order to obtain a modified polymer having excellent adhesion to metal, glass, EVOH, nylon and other polar resins, the present inventors added powdery polyolefin to the polyolefin. When cografting an unsaturated carboxylic acid or a derivative thereof (hereinafter referred to as unsaturated carboxylic acid, etc.) in the presence of ethylene using a radical initiator at a temperature lower than the melting temperature of the polyolefin, 100 parts by weight of the polyolefin is On the other hand, the molar ratio of unsaturated carboxylic acid, etc. to ethylene/unsaturated carboxylic acid, etc. is 0.3 to 5.0, and is 2 to 30.
A method for producing a modified polymer, which is characterized in that 0.1 to 20 parts by weight of a radical reaction initiator is fed into the system continuously or in at least 3 parts, solves the above problems. We have found a solution to this problem and have completed the present invention.

In the present invention, polyolefins are homopolymers of olefins such as ethylene, propylene, ■-butene, 3-methyl-butene-], ]■-hexene, 4-methyl-pentene-1,1-octene, or polymers of these olefins. A copolymer of two or more random or block copolymers or a copolymer containing these olefins as a main component and copolymerized with at least one of vinyl acetate, acrylic acid, methacrylic acid, acrylic acid alkyl ester, methacrylic acid alkyl ester, etc. It refers to polymers 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-l 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.

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.

As radical reaction initiators, compounds that generate free radicals,
Primarily organic peroxides are used. For example, dialkyl peroxide, dicumyl peroxide, t-butylcumyl peroxide, etc., acetyl peroxide, i-butyryl peroxide, octanoyl peroxide, lauroyl peroxide, benzoyl peroxide, 0-methyl Diacyl peroxides such as benzoyl peroxide, peroxydicarbonates such as di-i-propyl peroxydicarbonate, dino-ethylhexyl oxydicarbonate, t-butyl peroxyvivalate, t-butyl peroxylaurate, etc. peroxyesters, ketone peroxides such as methyl ethyl ketone peroxide and cyclohexanone peroxide, peroxyketals such as 1.1-bis-t-butylperoxycyclohexane and 2.2-bis-t-butylperoxyoctane, t Examples include hydroperoxides such as -butyl hydroperoxide and cumene hydroperoxide, azo compounds such as 2,2-azobisisobutyronitrile, and oxygen, but from the viewpoint of crosslinking efficiency and half-life temperature, benzoyl peroxide, Di-propylene carbonate is preferred. The amount of radical reaction initiator used is usually O per 100 parts by weight of polyolefin.
, 1 to 20 parts by weight, preferably 1 to IO parts by weight.

If the amount of the radical initiator is less than 0.1 part by weight, the grafting rate will be low and sufficient adhesiveness will not be obtained. When the amount exceeds 20 parts by weight, many side reactions such as decomposition and crosslinking occur, the MFR changes significantly compared to the polyolefin before modification, and moldability becomes difficult. In order to achieve sufficiently stable performance, 1.
Preferably, ~10 parts by weight are used.

Feeding the radical initiator into the co-grafting system is
A radical reaction initiator is dissolved in a solvent having low chain transfer properties and high solubility of the radical initiator and unsaturated carboxylic acid, and is fed into the cografting system continuously or in at least three portions.

Examples of the solvent include benzene, toluene, xylene, methyl acetate, etc. The amount of the solvent is preferably the minimum amount that can dissolve the radical reaction initiator, and is usually 5 to 20 times the amount of the radical reaction initiator. be. The feeding method varies depending on the co-grafting temperature, but it is fed in at least 3 portions, preferably 7 portions or more, or continuously.

The feeding time varies somewhat depending on the cografting temperature;
Usually 0.5 hours or more. If the feeding method is less than 3 parts or the feeding time is less than 0.5 hours, partial gelation will occur, which will cause problems in the molding process and will also impair the appearance after molding. Furthermore, sufficient adhesion cannot be obtained due to non-uniform grafting and a reduction in the amount of grafting due to a reduction in the amount of radicals effectively used.

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, etc., and cannot be said in general.
The amount is usually 2 to 30 parts by weight, preferably 3 to 20 parts by weight, based on 100 parts by weight of the polyolefin. If the amount of the unsaturated carboxylic acid or its derivative is less than 2 parts by weight, the grafting rate will decrease and sufficient adhesiveness will not be obtained. If the amount exceeds 30 parts by weight, the grafting rate will become too high and the resulting modified polymer will lose its polyolefin properties, especially good processability.If conditions are adopted that reduce the grafting rate, unreacted Since this increases, a large amount of solvent is required in the washing step after co-grafting, which is extremely disadvantageous in terms of cost and industrial production.

It is essential that the co-craft 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 20. If the amount of ethylene gas is lower than the molar ratio of 0.3 to the unsaturated carboxylic acid or its derivative, there will be no problem with gel formation or processability, but the grafting rate will be low and the adhesiveness will be lowered. On the other hand, if this molar ratio exceeds 5.0, the grafting ratio will increase, but the melt flowability will be greatly reduced, the adhesive strength will be reduced, and gelation will occur frequently, causing problems in molding processing.

The co-grafting method is preferably a method in which graft polymerization is carried out in a state where the powdery polyolefin is not dissolved or melted. More specifically, it is preferable to carry out the reaction at a temperature that is at least 30° C. lower than the peak melting point of the polyolefin. In order to increase the efficiency of co-grafting, it is preferable to carry out the co-grafting within the range of 100°C below the peak temperature to 30°C below the peak temperature.If the melting point of the polyolefin exceeds 30°C below the peak temperature, the polyolefin After co-grafting, a large amount of the modified polymer adheres to the wall of the reaction vessel, which is disadvantageous in industrial production at the post-treatment stage. If the peak temperature is lower than 100° C., the cografting rate will decrease, and the melt flowability of the modified polymer will also decrease significantly, making it impossible to obtain sufficient adhesion and moldability.

Although the reaction time cannot be absolutely defined depending on the decomposition temperature and co-grafting temperature of the radical initiator used, it is usually about 0.5 to 3 hours after the end of feeding the radical initiator.

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 purified modified polymer is purified to a state in which unreacted unsaturated carboxylic acids, etc. or reaction by-products remain at most 700 ppm or less. If the content exceeds 7 oopp'm, the adhesion may deteriorate.

In addition, modified polymers that exhibit sufficient adhesive properties.

The grafting amount of unsaturated carboxylic acid or its derivative is 1
The amount of grafted ethylene must be at least 31% by weight, and the MFR (JIS K 72102.16kg load) must be in the range of 0.5 to 50 times that before co-crafting. If the lid is less than the above or the MFR is outside the above 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, polyolefin, oxygen barrier resin such as nylon or EVOH, gold CI: foil, Combined with paper etc.
It can be used as a reinforcing layer or adhesive layer in multilayer laminates.

The blend ratio of the modified polymer and the polyolefin in the modified polymer composition is such that the content of unsaturated carboxylic acids, etc. is 0.
, 1% by weight or more, and the grafted ethylene content is preferably 0.01% by weight or more, and if it is less than the above, sufficient performance will not be obtained.

Furthermore, since it has extremely good affinity with polyolefins and also has affinity to some extent 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.

Well-known additives and compounding agents may be added to the modified polymer and the 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, L sulfur-based stabilizers such as dilaurylthiodipropionate and 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 stabilizers, pensifuge-based stabilizers, benzotriazole-based stabilizers, etc. 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, lauryl soda sulfate,
Sulfates such as lauryl chlorosulfonate, phosphorus oxides such as monooleyl phosphate and dioleyl phosphate, amides such as N,N-dimethyl-acetic acid soda oleate amide, quaternary ammonium such as lauryl trimethyl ammonium chloride, lauryl dimethyl benzyl ammonium chloride, etc. Examples include salts, betaines such as stearyl dimethyl betaine and lauryl dihydroxy betaine, and polyethylene glycol type nonionic antistatic agents.

N fuels include chlorinated paraffin, chlorinated polyethylene, chlorentic anhydride, bisphenol A tetrabromide,
Halogenated flame retardants such as tetrabrominated phthalic anhydride, dibromodichloropropane, trischloroethyl phosphate,
Examples include phosphorus flame retardants such as bischloropropyl chloroethyl phosphate and phosphoric acid esters, and non-halogen type W 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 compounds or mixtures, alcohol-based lubricants, metal soaps, etc. 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, etc.

The crosslinking efficiency can also be increased by using in combination quinonedioxime compounds such as p-quinonedioxime and dibenzoylquinonedioxime, or compounds such as divinylbenzene, vinyltoluene, and 1.2 polybutadiene.

[Example] Examples and comparative examples are shown below. Melt flow rate (
MFR) was measured according to JIS K 7210 (216 kg load). Quantification of unsaturated carboxylic acids, etc. and ethylene was performed using 13CN M R1 infrared absorption spectrum.

(Example 1) Polypropylene powder (MFR (230°C) 22 g/lo minute average particle size 25
0LLm), 3.0 g of maleic anhydride, and after replacing with nitrogen, 08 g of ethylene was added, and then the inside of the system was
The temperature was raised to 00°C.

Next, 15g of benzoyl peroxide, 10rr of toluene + J2
A solution consisting of was added dropwise over 15 hours, and the temperature was maintained at 100° C. for an additional 1.5 hours to carry out a co-grafting reaction.

After the reaction was completed, the modified polymer was washed five times with acetone at 300 m°C at 30°C, and then dried under reduced pressure. The MFR (230°C) of the obtained modified polymer was 300 g/10 min, and the maleic anhydride co-grafted to the modified polymer was 1
．． 68 wt%, and ethylene was 0.65 wt%.

Further, the amount of remaining unreacted substances was i4 oppm, and the amount of reaction by-products was 120 ppm.

(Example 2) The same procedure as in Example 1 was conducted except that 30 g of maleimide was used instead of 30 g of maleic anhydride. The MFR (230°C) of the obtained modified polymer is 1
At 45 g/10 min, maleimide cografted to the modified polymer was 1°89 wt% and ethylene was 0.49 wt%.
Met. Further, the amount of remaining unreacted substances was soppm, and the amount of reaction by-products was 390 ppm.

[Example 3] Instead of 50 g of polypropylene powder, 50 g of high-density polyethylene powder (MFR (190°C)) 18 g, 710 minutes
Density 0, 958 g/am3 Average particle size 320 μm
) was used and the co-grafting temperature was 90°C, but the same procedure as in Example 1 was carried out. MFR of the obtained modified polymer
(190°C) was 56.2 g/10 minutes, maleic anhydride co-grafted to the modified polymer was 1.81 wt%, and ethylene was 0.67 wt%. Further, the amount of remaining unreacted substances was 160 ppm, and the amount of reaction by-products was +7 oppm.

(Example 4) Instead of 50 g of polypropylene powder, 50 g of linear low density polyethylene powder (MFR (190°C)) 20 g/10
min, density 0, 918 g/cm3 average particle size 25
The same procedure as in Example 1 was carried out, except that di-l-propyl peroxydicarbonate was used as the initiator and the cografting temperature was 70°C. M of the obtained modified polymer
The FR (190°C) was 36.8 g/10 min, and the maleic anhydride co-grafted to the modified polymer was 1.71 wt%.
, ethylene was 0.62 wt%. Further, the amount of remaining unreacted substances was 130 ppm, and the amount of reaction by-products was 200 ppm.

(Example 5) Instead of 50 g of polypropylene powder, 50 g of ethylene-propylene random copolymer powder (MFR (230 ° C.
) 17 g/10 min, ethylene content 5.2 wt%, average particle size 340 LLm), and the co-grafting temperature was 90°C.
The same procedure as in Example 1 was carried out except that.

The MFR (230°C) of the obtained modified polymer was 120g/
In 10 minutes, maleic anhydride co-grafted onto the modified polymer was 1.81 wt%, ethylene was (L) 59 wt%, remaining unreacted substances were 170 ppm, and reaction by-products were 1100 ppm. .

(Example 6) Example 1 except that the ethylene feed amount was 0.4 g.
I did the same thing. MFR of the obtained modified polymer (23
0°C) was 390 g/10 min, maleic anhydride co-grafted to the modified polymer was 1.21 wt%, and ethylene was 0.38 wt%.

Further, the amount of remaining unreacted substances was 110 ppm, and the amount of reaction by-products was 120 ppm.

(Example 7) The same procedure as in Example 1 was conducted except that 0.8 g of benzoyl peroxide and 6 mg of toluene were used.

The MFR (230°C) of the obtained modified polymer was 80.6.
g/10 min, 1.31 wt% maleic anhydride and 0.53 wt% ethylene cografted onto the modified polymer.
Met. Further, the amount of remaining unreacted substances was 160 ppm, and the amount of reaction by-products was 140 ppm.

(Example 8) Example 8 except that a solution of 15 g of benzoyl peroxide dissolved in 10 m (2) of toluene was divided into 5 portions, and 115 amounts were fed into the system at the start of the reaction, and then 115 amounts were fed into the system every 15 minutes. It was carried out in the same manner as in 1. MF of the obtained modified polymer
R (230° C.) was 176 g/10 min, maleic anhydride co-grafted to the modified polymer was 1.38 wt%, and ethylene was 0.52 wt%. Further, the amount of remaining unreacted substances was tsoppm, and the amount of reaction by-products was 150 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 450g/
At 10 minutes, 0.26 wt% maleic anhydride was grafted onto the modified polymer.

Further, the amount of remaining unreacted substances was 380 ppm, and the amount of reaction by-products was 70 ppm.

(Comparative Example 2) 1.5 g of benzoyl peroxide and 10 ml of toluene,
The same procedure as in Example 1 was carried out except that the entire amount was charged first.

The MFR (230°C) of the obtained modified polymer is 70.6g
/10 minutes, maleic anhydride and ethylene were 0.62 wt% and 0.28 wt% cografted onto the modified polymer, respectively.

Further, the amount of remaining unreacted substances was 150 ppm, and the amount of reaction by-products was 20 ppm.

(Comparative Example 3) Example except that a solution of 1.5 g of benzoyl peroxide dissolved in 10 rr + 12 toluene was divided into two parts, and half of it was fed into the system at the start of the reaction, and the rest was fed into the system at once after 20 minutes of reaction. It was carried out in the same manner as I. The obtained modified polymer (7
) MFR (230°C) I:1B at 55 g/10 min, maleic anhydride co-grafted onto the modified polymer is 0.72
wt%, and ethylene was 0.31 wt%. In addition, the remaining unreacted substances are 190 ppm, and the reaction by-products are 250 ppm.
It was pm.

Compared to the modified polymers obtained in Comparative Examples 2 and 3, which were obtained by continuously feeding a radical reaction initiator,
The film tended to contain a lot of gel, and the moldability and film appearance were somewhat degraded.

(Comparative Example 4) 0.8 g of maleic anhydride and 0.8 g of ethylene. 15g,
1. benzoyl peroxide. The same procedure as in Example 1 was conducted except that Og and toluene were changed to 6 mβ. The obtained modified polymer (
7) MFR (230'C) is 110 g/10 min and maleic anhydride co-grafted to the modified polymer is 0.39
wt%, and ethylene was 0.15 wt%. In addition, the remaining unreacted substances are 280 ppm, and the reaction by-products are 40 ppm.
It was m.

(Comparative Example 5) The same procedure as in Example 1 was carried out except that ethylene was changed to 7 g. The MFR (230°C) of the obtained modified polymer was 9.8
g/10 min, 2.54 wt% maleic anhydride and 1.02 wt% ethylene cografted onto the modified polymer.
Met. Further, the amount of remaining unreacted substances was 7 oppm, and the amount of reaction by-products was 400 ppm.

(Comparative Example 6) The same procedure as in Example 1 was conducted except that 1.5 g of maleic anhydride, 0.4 g of ethylene, 0.03 g of benzoyl peroxide, and 3 ml of toluene were used. The MFR (230°C) of the obtained modified polymer was 30.2 g/10 min, and the maleic anhydride co-grafted to the modified polymer was 0.06 w.
t%, and ethylene was 0.02wt%. Further, the amount of remaining unreacted substances was 70 ppm, and the amount of reaction by-products was 80 ppm.

(Reference example) The modified polymers obtained in Examples 1 to 8 and Comparative Examples 1 to 6 were mixed with polypropylene (MFR (230°C) 5.5 g/10
), high density polyethylene (MFR (190℃) 6.2
g/10 min density 0.954 g/cm'), linear low density polyethylene (MFR (190°C) 4.8 g/10 min density 0.915 g/c+++3) ethylene-propylene copolymer (MFR (230°C) A modified polymer composition having a polymer content of 10% by weight was obtained by blending it with a resin selected from 4.3 g/10 minutes and a density of 0883 g/c (3) in the proportions shown in Table 2.

The modified polymer composition and EVOH (ethylene content: 3
2 mol%) using a two-type, two-layer coextrusion multilayer T-die film forming machine with a diameter of 40 mm and a diameter of 45 mm, at a die temperature of 2.
Two types of two-layer films (each layer thickness: 30 μm) were molded at 20° C. using a chill roll with water flowing through it. The obtained laminate film was subjected to a 180° peel test at a peel speed of 300 m.
Evaluation was made at 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 in a polymer composition blended with polyolefin, F.
It can be seen that it exhibits high adhesive strength with VOH.

(Left below) [Effects of the Invention] Ethylene, unsaturated carboxylic acid, etc. are added to the powdery polyolefin of the present invention per 100 parts by weight of the polyolefin.
, J ~ 20 parts by weight of a radical initiator is fed into the system either continuously or in small amounts (either in three parts) to co-graft the modified polymer, which improves performance such as adhesion, printability, and paintability. It can be greatly improved.

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

Claims (3)

[Claims] (1) When co-grafting an unsaturated carboxylic acid or a derivative thereof to a powdery polyolefin in the presence of ethylene using a radical initiator at a temperature lower than the melting temperature of the polyolefin, based on 100 parts by weight of the polyolefin. , the unsaturated carboxylic acid or its derivative has an ethylene/unsaturated carboxylic acid or its derivative molar ratio of 0
．． 3 to 5.0 parts by weight, using 2 to 30 parts by weight,
A method for producing a modified polymer, which comprises feeding 0.1 to 20 parts by weight of a radical reaction initiator into the system, either continuously or in at least three parts. (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. Method described. (3) 2 to 30 parts by weight of unsaturated carboxylic acid or its derivatives per 100 parts by weight of powdery polyolefin;
Claim 1, characterized in that ethylene is used in an amount of 0.3 to 5.0 (as a molar ratio of ethylene/unsaturated carboxylic acid or derivative thereof) to the unsaturated carboxylic acid or derivative thereof. Method for producing modified polymer.