JPS588683B2 - Method for producing modified polyolefin - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for modifying polyolefin, and more specifically, the present invention relates to a method for modifying polyolefin, and more specifically, polyolefin is modified by modifying polyolefin with one or two alicyclic carboxylic acids having a cis-type non-conjugated double bond in the ring or anhydrides thereof. After completion of the addition reaction, the above is chemically bonded to a modified polyolefin using a radical generator in an extruder, and 0.1 to 0.1 to
The modified polyolefin is produced by reacting one or more kinds of compounds having a plurality of alcoholic hydroxyl groups or amino groups such as 2.0 molar equivalents of polyhydric alcohols, polyvalent amines, and amino alcohols in the molten state of the modified polyolefin. The unreacted carboxylic acid or its anhydride remaining in the polyolefin is effectively fixed in the polyolefin, and the unreacted carboxylic acid or its anhydride causes an irritating odor during production, processing, or molding of the modified polyolefin. The present invention relates to a method for producing a modified polyolefin, which is characterized by obtaining a modified polymer that suppresses escape and has adhesive properties superior to polyolefins modified with the carboxylic acid and its anhydride.

Polyolefins, such as polyethylene, polypropylene, or polybutene-1, have no polar groups in their polymer chains, so they are nonpolar, and they are generally crystalline, so they have many practical advantages, but on the other hand, glass fibers, It has poor adhesion to metals or polar polymers, and also lacks printability, dyeability, etc., which greatly limits its range of use.

In order to improve these drawbacks of polyolefins, attempts have been made to graft polar monomers onto polyolefins and introduce polar groups into polyolefins. For example, methods of adding maleic anhydride to polypropylene, or endo-bicyclo-
A method of adding [2.2.1]-5-heptene-2,3-dicarboxylic acid or its anhydride has been proposed.

The modification reaction of polyolefin with these polar monomers can also be carried out by dissolving the polyolefin in a high temperature solvent and adding the polar monomer and radical generator.
In industrial production, many steps such as polymer dissolution, reaction, reprecipitation, filtration, and drying are required, which is impractical, and a preferred method is to carry out these modification reactions in an extruder.

For the modification reaction using an extruder, for example, polyolefin powder or pellets are supplied to an extruder together with a polar monomer and an appropriate radical generator, and the modified polyolefin is passed through the extruder at a temperature higher than the melting point of the polyolefin, thereby obtaining a modified polyolefin. This is an extremely practical method in terms of economy and workability.

However, the modified polyolefin obtained by the modification reaction in an extruder inevitably contains a small amount of unreacted polar monomer. A part of the molten polymer escapes to the outside from the surface of the molten polymer extruded from the pent hole or die, and may also escape during secondary processing of the modified polyolefin, such as during high-temperature kneading with glass fibers, or during high-temperature kneading of the modified polyolefin. Even during molding, some of it escapes to the outside, often causing a pungent odor.

In order to suppress the generation of this irritating odor, unreacted polar monomers in the modified polyolefin can be removed, but this can be done by dissolving the modified polyolefin in a solvent and reprecipitating it, or by dissolving only the polar monomer without dissolving the modified polyolefin. It requires extraction with a solvent that dissolves it, and is not industrially practical.

The present inventors have arrived at the present invention as a result of intensive research to overcome the above-mentioned drawbacks that are inseparable from polyolefins modified by extruders.

That is, the present invention involves an addition reaction when an alicyclic carboxylic acid or its anhydride having a cis-type non-conjugated double bond in the ring is continuously added to a polyolefin in the presence of a radical generator in an extruder. After completion of the process, 0.1 to 2.0 equivalents of alcoholic hydroxyl groups or amine groups such as polyhydric alcohols, polyhydric amines, and amino alcohols are added to all the carboxylic acids or their anhydrides contained in the modified polyolefin. By reacting one or more compounds containing at least two of these or both in the molten state of the modified polyolefin, the unreacted carboxylic acid monomer remaining in the carboxylic acid-modified polyolefin is converted into the polyhydric alcohol, the polyolefin, and the like. It is fixed in modified polyolefin as an ester compound or amide compound such as a functional amine or amino alcohol to minimize the irritating odor caused by unreacted carboxylic acid monomer escaping during heating and melting during production, processing, or molding of the modified polymer. This invention relates to a method for modifying polyolefins, which is characterized by minimizing the

The first feature of the present invention is that the polyhydric alcohol, amino alcohol, or polyhydric amine added to the carboxylic acid-modified polyolefin selectively reacts with unreacted carboxylic acid or anhydride monomers among all carboxylic acids or anhydrides. Therefore, the amount of the carboxylic acid or its anhydride (the carboxylic acid or its anhydride chemically bonded to the polyolefin and the unreacted carboxylic acid or its anhydride monomer) is 2 molar equivalents or less in the modified polyolefin. The unreacted carboxylic acid monomer remaining in the modified polyolefin is effectively fixed by a small amount of polyhydric alcohol, polyvalent amine or amino alcohol, preferably 1.2 molar equivalent or less, and during subsequent heating and melting of the modified polyolefin. This eliminates the generation of irritating odors due to the escape of unreacted carboxylic acid monomers.

The second feature of the present invention is that the modified polyolefin, in which unreacted monomers are fixed by the addition of a small amount of polyhydric alcohol, polyhydric amine or amino alcohol, can be prepared by using carboxylic acid without adding polyhydric alcohol, polyhydric amine or amino alcohol. It has adhesion to metals or glass fibers which is as good as or better than that of modified polyolefins made of polyolefins or their anhydrides. When the amount is 1.2 molar equivalent or less based on the total carboxylic acid or anhydride, it means that the adhesive has extremely excellent adhesion to metal or glass fiber.

Moreover, since the polyhydric alcohol, polyhydric amine or amino alcohol added is in an extremely small amount, the excellent mechanical or thermal properties inherent to the polyolefin are not affected at all.

Furthermore, the polyolefin modified with polyhydric alcohol, polyhydric amine or amino alcohol added by the method of the present invention is equivalent to or better than polyolefin modified with carboxylic acid or its anhydride to which polyhydric alcohol, polyhydric amine or amino alcohol is not added. improved printability,
It has adhesion to paintable and dyeable metal plating films or metal vapor deposited films.

The third feature of the present invention is that by kneading the modified polyolefin glass fiber obtained by the method of the present invention, a glass fiber reinforced polyolefin having extremely excellent workability and mechanical properties can be obtained.

Glass fiber-reinforced polyolefin with excellent mechanical properties can be obtained by reinforcing polyolefin modified with alicyclic carboxylic acid or its anhydride having a cis-type non-conjugated double bond in the ring with glass fiber. Although it is known, the practical method for producing modified polyolefins is by using an extruder, and in this case, some unreacted carboxylic acid or anhydride is always included in the modified polyolefin, so a step of kneading glass fibers is required. Alternatively, during the process of molding the obtained glass fiber-reinforced polyolefin, the generation of an irritating odor due to the escape of unreacted carboxylic acid was unavoidable.

However, according to the method of the present invention, unreacted carboxylic acid or anhydride is easily and selectively fixed in the polyolefin by adding a small amount of polyhydric alcohol, polyhydric amine, or amino alcohol, so there is no irritation in the above steps. Odor generation is significantly suppressed, and is equivalent to or better than conventional glass fiber reinforced polyolefins modified with unsaturated carboxylic acids or their anhydrides without the addition of polyvalent amines, polyhydric alcohols, or amino alcohols. A glass fiber reinforced polyolefin with excellent mechanical properties can be obtained.

The polyolefin in the present invention includes, for example, polyethylene, polypropylene, ethylene-propylene copolymer,
Poly-α-olefins such as polybutene-1 or blends thereof.

Preferred examples of alicyclic carboxylic acids having a cis-type non-conjugated double bond in the ring or their anhydrides include cis-4-cyclohexene-1,2-dicarboxylic acid, endobicyclo[2
-2.1]-5-heptene-2,3-dicarboxylic acid and anhydrides thereof.

Modification of polyolefin with unsaturated carboxylic acid or its anhydride in the present invention is carried out using an extruder.

Generally, polyolefin pellets or powder, an unsaturated carboxylic acid or anhydride, and a suitable radical generator are fed separately, with or without mixing, to an extruder and passed through the extruder at a temperature above the melting point of the polyolefin. A denaturation reaction is carried out by doing this.

The addition of the polyfunctional organic compound such as polyhydric alcohol, polyvalent amine or amino alcohol of the present invention is carried out after the above modification reaction, and the polyfunctional organic compound is added to the modified polyolefin obtained by the above modification reaction. The mixture is mixed and passed through an extruder again at a temperature equal to or higher than the melting point of the polyolefin to cause a reaction.

The polyfunctional organic compounds of the present invention include polyhydric alcohols, polyhydric amines, and amino alcohols, and preferred examples of polyhydric alcohols include ethylene glycol, 1,4-butanediol, 1,6-hexanediol, and propylene. It is an organic compound having at least two alcoholic hydroxyl groups such as glycol, glycerin, pentaerythritol, and polyethylene glycol or polypropylene glycol having a molecular weight of 40,000 or less.

Preferred examples of polyvalent amines having at least two amino groups include ethylenediamine, trimethylenediamine, hexamethylenediamine, paraphenylenediamine, benzidine, diethylenetetramine, tetramethylenepentamine, and polyethyleneimine with a molecular weight of 40,000 or less. It is an organic compound.

Preferred examples of amino alcohols include ethanolamine, 3-amino-1-propanol, and the like.
It is a compound having at least one amine group and at least one alcoholic hydroxyl group.

The polyhydric alcohol, polyhydric amine, and amino alcohol are not limited to these examples.

In the present invention, the amount of polyhydric alcohol, polyhydric amine, or amino alcohol to be added and reacted with unsaturated carboxylic acid or its anhydride-modified polyolefin is 0.00% relative to the total carboxylic acid or anhydride contained in the modified polyolefin.
1 to 2.0 molar equivalents, preferably 0.2 to 1.2 molar equivalents.

If the amount of polyhydric alcohol, polyhydric amine, or amino alcohol is 2 molar equivalents or more based on the total amount of carboxylic acids, the adhesiveness of the modified polyolefin will decrease, which is undesirable. If the amount is 0.1 molar equivalent or less, unreacted carboxylic acid Alternatively, the anhydride is fixed in the polyolefin, and the effect of suppressing the generation of irritating odor during heating becomes insufficient.

In particular, in the case of 0.2 molar equivalent or more and 1.2 molar equivalent or less, not only will the irritating odor during heating be sufficiently suppressed, but the adhesive strength to metals, glass, etc. will be due to a simple unsaturated carboxylic acid or its anhydride. It is most preferable because it is significantly improved compared to modified polyhirefin.

Next, the present invention will be explained in detail by way of examples.

Note that all parts in the examples indicate parts by weight.

Example 1 90 parts of crystalline polypropylene pellets with a melt index of 1.2, 10 parts of crystalline polypropylene powder with a melt index of 5.0, endobicyclo [2.2.1
] After mixing 1 part of -5-heptene-2,3-dicarboxylic anhydride and 0.5 part of ditertiary butyl peroxide, an extruder (screw diameter 40 r IL mL/D = 25, screw rotation speed 60r
．． p. m. Modified polypropylene pellets were obtained by passing through the solution.

The obtained modified polypropylene pellets had 0.20% by weight of endobicyclo[2,2,1-5-heptene-2,3-dicarboxylic anhydride chemically bonded thereto, and 0.53% by weight of The carboxylic acid anhydride remains unreacted in the modified polypropylene.

(The remaining carboxylic acid anhydride exited the system through a vent hole near the tip of the extruder and was recovered by a cooler.

) When this modified polypropylene 3 was heated and melted and molded, the pungent odor of endobicyclo[2.2.1]-5-heptene-2.3-dicarboxylic anhydride was noticeable.

This modified polypropylene pellet contains all the endobicyclo [2.2.1] contained in the modified polypropylene.
]-5-heptene-2,3-dicarboxylic anhydride and equimolar amounts of ethylene glycol, 1,4-butanediol, 1
・6-hexanediol, tetraethylene glycol,
Six types of modified polypropylene pellets (referred to as polyhydric alcohol-modified polypropylene) were obtained by mixing glycerin and pentaerythritol and passing the mixture through an extruder set at 200° C. to perform an esterification reaction.

Table 1 shows the amount of unreacted carboxylic acid anhydride remaining in these polyhydric alcohol-modified polypropylenes, the esterification rate, and the peel strength with aluminum foil (thickness 0.1 mm).

As is clear from Table 1, polyhydric alcohols are unreacted endobicyclo[2.2.1]-5-heptene-2.3~
Dicarboxylic acid anhydride is selectively esterified and fixed in modified polypropylene to prevent irritating odors during heat-melt processing, and the resulting polyhydric alcohol-modified polypropylene is superior to modified polypropylene without polyhydric alcohol added. Note (1) Ratio of the number of moles of added polyhydric alcohol to the number of moles of total carboxylic acid anhydride in the modified polypropylene (2) Polypropylene Endo-bicyclo-[2.2.1]-5-heptene-2 remaining in the modified polypropylene without adding alcohol or reacting with polyhydric alcohol.
-3-dicarboxylic anhydride.

(3) Unreacted endo-bicyclo-[2.2.1]-5-heptene-2.3 not additionally bonded to polypropylene
- Esterification rate of dicarboxylic anhydride (4) Endo-bicyclo- [2.2.1]- additionally bonded to polypropylene
Esterification rate of 5-heptene-2,3-dicarboxylic anhydride (5) Each modified polypropylene film with a thickness of 0.1 mm was sandwiched between two sheets of aluminum foil with a thickness of 0.1 mm, and heated at 200°C.
The samples were bonded under pressure at 10 kg/cm2 for 2 minutes using a hot press, and then cut into 2 cm wide pieces, and the peel strength was measured using an Instron tensile universal testing machine at a tensile speed of 5 cm/mix.

Example 2 Modified polypropylene obtained in Example 1 without the addition of polyhydric alcohol (Experiment No. 1), modified polypropylene with the addition of ethylene glycol (Experiment No. 2), modified polypropylene with the addition of glycerin (Experiment No. 6), and modified with the addition of pentaerythritol For each 140 parts of pellets of polypropylene (Experiment No. 7), 40 parts of crystalline polypropylene pellets with a melt index of 15, chopped glass fiber strands surface-treated with γ-aminopropyltriethoxysilane (glass fibers with a diameter of 13 microns)
After mixing 20 parts of 00 pieces (bundled and cut into lengths of 6 pieces) in a tumbler mixer, an extruder set at 230°C (screw diameter 40 mm, L/D = 25, screw
r. p, m. 49) Modified polypropylene pellets containing glass fibers were obtained by passing the pellets through the pellets.

At this time, in the case of modified polypropylene to which no polyhydric alcohol was added, a markedly pungent odor was generated from the molten resin strand discharged from the extruder die, but in the case of modified polypropylene to which polyhydric alcohol was added. Almost no irritating odor was generated.

Next, a test piece was made by injection molding from the obtained glass fiber-containing modified polypropylene pellets, but when the modified polypropylene was made without adding polyhydric alcohol during injection molding, a pungent odor was generated. In the case of modified polypropylene with added alcohol, no irritating odor was detected at all.

Table 2 shows the results of measuring the physical properties of each of the obtained test pieces, and the ones using modified polypropylene treated with polyhydric alcohol had further improved mechanical properties than the ones that did not use modified polypropylene. ing.

Example 3 To 100 parts of high-pressure polyethylene pellets having a melt index of 7.0 and a specific gravity of 0.925, 1 part of endo-bicyclo-[2.2.1]-5-heptene-23-dicarboxylic anhydride, bis(tertiary) 0.3 parts of (butylperoxyisopropyl)benzene was mixed therein, the extruder used in Example 1 was set at 190°C, and the mixture was fed into the extruder to obtain modified polyethylene pellets.

The modified polyethylene pellets contained 0.30% by weight of endo-bicyclo-[2.2.1]-5-heptene-2.
3-dicarboxylic anhydride is chemically bonded, and 0.52
It contained % by weight of unreacted dicarboxylic anhydride.

This modified polyethylene generates a pungent odor due to unreacted dicarboxylic anhydride during melt processing such as film molding, and its adhesive strength with aluminum is 2. 0 kg/cm (Experiment No. 12).

To this modified polyethylene was added 1.5% by weight of polyethylene glycol (molecular weight 400), that is, 0.75 molar equivalent of polyethylene glycol based on all the carboxylic anhydrides contained in the modified polyethylene, and the same extruder was added. (2
The esterification reaction was carried out by passing the mixture to 00°C.

As a result, 81% of the unreacted carboxylic acid was esterified, the amount of unreacted carboxylic acid was reduced to 0.1% by weight, and the irritating odor during the molding process was almost eliminated.

Moreover, the adhesive strength with aluminum was 2.8 kg/cm (experiment number 13).

Example 4 Ethylene content 7.2% by weight, melt index 140
100 parts of crystalline ethylene-propylene copolymer, endo-bicyclo-[2.2.1]-5-heptene-2.
After mixing 2 parts of 3-dicarboxylic anhydride and 0.5 part of ditertiary butyl peroxide, modified ethylene propylene copolymer pellets were made by passing through the same extruder used in Example 1 set at a temperature of 190°C. Obtained.

The obtained modified polypropylene pellets were chemically bonded with 0.50% by weight of endo-bicyclo-[2.2.1]-5-heptene-2.3-dicarboxylic anhydride, and 1 .02% by weight of the dicarboxylic anhydride remained unreacted in the modified polypropylene.

When this modified ethylene-propylene copolymer is heated and melt-molded, unreacted endo-bicyclo-[2.2
・1]-5-Heptene-2,3-dicarboxylic anhydride escaped, and a significant pungent odor was observed.

In this modified ethylene-propylene copolymer pellet,
All endo-bicyclo- [2.2.
1] Add and mix 0.4 molar equivalent of 1,4-butanediol, glycerin, or pentaerythritol to -5-heptene-2,3-monodicarboxylic anhydride and mix at 190°C.
The mixture was passed through an extruder set to 1 and subjected to an esterification reaction to obtain polyhydric alcohol-modified ethylene-propylene copolymer pellets.

Table 3 shows the amount of residual carboxylic anhydride, esterification rate, and peel strength with aluminum foil of these polyhydric alcohol-modified ethylene-propylene copolymers.

As is clear from the table, the polyhydric alcohol selectively esterifies unreacted carboxylic acid anhydride, fixes it in the modified polymer, and significantly reduces the irritating odor during processing.
Moreover, the adhesion to aluminum foil is also significantly improved.

Example 5 Endo-bicyclo-[
2.2.1]-5-heptene-2.3 monodicarboxylic anhydride-modified polypropylene pellets, all endo-bicyclo-[2.2.1]-5- contained in this modified polymer
Heptene-2,3 monodicarboxylic anhydride (0.73% by weight
) was added and mixed with 1.0 molar equivalent of ethylenediamine, and melt-kneaded for 5 minutes using a Brabender plastograph set at 190°C to obtain modified polypropylene.

1,3-diaminopropane, m-
A modified polymer was obtained using phenylene diamine, p-phenylene diamine, and benzidine.

(These are polyamine-modified polypropylene) Table 4
The amount of unreacted dicarboxylic anhydride remaining in these polyvalent amine-modified polypropylenes, the amidation rate, and the peel strength with aluminum foil were shown.

As is clear from the table, unreacted dicarboxylic anhydride is selectively amidated with a polyvalent amine and fixed in the modified polypropylene, which generates almost no irritating odor when melted by heating, and has excellent peel strength from aluminum foil. has also improved significantly.

(2) Dicarboxylic anhydride remaining in modified polypropylene without being added to polypropylene or reacting with polyvalent amine (3) Unreacted dicarboxylic anhydride not added to polypropylene Amidation rate of acid (4) Amidation rate of dicarboxylic anhydride additionally bonded to polypropylene (5) Notes to Table 1 (5)
)Same as.

Example 6 Endo-bicyclo-[2.2.1]-5 obtained in Example 4
-Heptene-2,3-carboxylic anhydride-modified ethylene-propylene copolymer pellets contain all the endo-bicyclo-[2,2,1]-5-heptene-2,3-anhydride dicarboxylic acid contained in this modified polymer. Molar ratio to acid: 1.
0 monoethanolamine or 3-amino-1-propanol was added and mixed, and melt-kneaded for 5 minutes using a Prapendar Plastograph set at 190°C to obtain a modified polymer.

As shown in Table 5, as in the case of polyhydric alcohol or polyhydric amine modification, almost no irritating odor was observed during hot melt molding, and the peel strength with aluminum foil was significantly improved.

Claims (1)

[Claims] 1 Modified polyolefin is produced by chemically bonding one or more alicyclic carboxylic acids or anhydrides thereof having a cis-type non-conjugated double bond in the ring to polyolefin using a radical generator in an extruder. When producing a polyolefin, after the completion of the addition reaction, the total amount of carboxylic acid or its anhydride contained in the modified polyolefin is 0.
．． 1 to 2.0 molar equivalents of polyhydric alcohol, polyhydric amine,
By reacting one or more compounds having a plurality of alcoholic hydroxyl groups or amine groups such as amino alcohol in the molten state of the modified polyolefin, the unreacted carboxylic acid or its anhydride remaining in the modified polyolefin can be removed. A method for producing a modified polyolefin, which comprises fixing a substance in the polyolefin.