JPH041231A - Production of copolyamide resin - Google Patents

Abstract

PURPOSE:To facilitate the formation of a copolyamide resin wherein a polyamide is grafted onto a polyolefin in a high degree of grafting by heating a polyolefin having a carboxyl group and/or an acid anhydride group and a lactam in the presence of a specified compound. CONSTITUTION:A polyolefin having a carboxyl group and/or an acid anhydride group (e.g. ethylene/methacrylic acid copolymer) and a lactam (e.g. caprolactam) are heated in the presence of a P compound (e.g. 75% phosphoric acid).

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a method for polymerizing a copolymer in which a polyamide is grafted onto a polyolefin, and its purpose is to provide a polymerization method with an extremely high grafting rate. The object of the present invention is to provide a copolymer in which a polyamide is grafted onto a polyolefin at a high grafting rate, which has not been easily obtained up to now.

(Prior Art and Problems) It is easy for those with ordinary chemical knowledge to think that a carboxyl group in a polyolefin and a polyamide will be chemically bonded through an amide bond. In fact, there are many cases where patents claim that chemical bonding occurs without sufficient evidence. However, as can be seen in the paper ``Heat-resistant adhesion and melt rheology of polymer complexes of ionomers and polyamide oligomers'' published in the Journal of the Japan Society of Rheology, Vol. 14, page 117 (198B), carboxyl groups in polyolefins It is not always acceptable for the amino groups in the polyamide to form a covalent amide bond.

Conventionally, methods for graft polymerizing a polyamide onto a polyolefin having a carboxyl group include a method of melt-mixing the polyolefin having a carboxyl group and an already polymerized polyamide, and a method in which a monomer that forms a polyamide in the presence of the polyolefin having a carboxyl group is used. A method of polymerizing has been proposed.

In the case of the former method, since the polymeric compound is a polymer, the mixing entropy is small, and therefore, polymeric compounds with different molecular structures generally do not disperse and form separate domains. Polyolefins and polyamides having carboxyl groups and/or acid anhydride groups also have completely different structures and form completely separate domains, so even if a chemical reaction occurs with each other, it is only at the interface. As seen in Japanese Patent Publication No. 81-52174, the purpose of chemical reactions in such blend systems is generally to improve the adhesive strength between the respective domains, so it is possible that some kind of reaction only occurs at the interface. That's enough. However, in any case, it is clear that a graft polymer having a high overall grafting ratio cannot be obtained by such a method.

Regarding the latter method, for example,
No. 474 proposes a method of polycondensing monomers for forming a polyamide in the presence of a polyolefin having a carboxyl group or an acid anhydride group. Lactams, dibasic acid diamine salts, and ω-amino acids are mentioned as monomers that form polyamides, but at least dibasic acid diamine salts contain diamines, so two carboxyl groups react with the polyamide. Therefore, crosslinking occurs and an insoluble and infusible reactant is obtained. In order to prevent this, a polyolefin having extremely few carboxyl groups must be used, but if this is done, the grafting rate will decrease. In fact, Example 1 of Japanese Patent Publication No. 46-5474 uses a polyolefin having a carboxyl group and hexamethylene diammonium adipate, and 24.7%
This means that the remaining 72.8% was not grafted and became homopolyamide.

When a lactam or ω-amino acid is used, under general polymerization conditions, for example, Example 3 of Japanese Patent Publication No. 4B-5474.
Under such conditions, the polymerization of the lactam or ω amino acid itself proceeds rapidly, so the probability that the monomer or the polymerized polyamide will react with the carboxyl group of the polyolefin is not necessarily high. Furthermore, when the molecular weight of the homopolyamide increases beyond a certain level, its compatibility with the polyolefin decreases, forming lateral domains as in the case of a polymer blend, and they react with each other only at the interface. For this reason, the grafting rate is still low, and the grafting rate in Patent Example 3 is also 32.6%.

An object of the present invention is to provide a polymerization method that can easily produce a copolymer in which a polyamide is grafted onto a polyolefin chain at a high grafting rate.

(Means for Solving the Problems) That is, the present invention provides a polyolefin having a carboxyl group and/or an acid anhydride group (hereinafter abbreviated as carboxyl group, etc.) and a lactam in the presence of a phosphorus compound, substantially in water. This is a method for polymerizing a copolymer in which polyamide is graft-polymerized on a polyolefin chain, which is characterized by heating in the absence of polyolefin.

In the present invention, if there are no impurities, ring-opening polymerization of the lactam will not occur with just the lactam and the phosphorus compound, but polymerization will occur starting from the presence of carboxyl groups and the like. Therefore, in theory, all polyamides grow from carboxyl groups etc. bonded to polyolefins, so an extremely high grafting rate can be obtained.

Furthermore, a feature of the copolymer obtained by the present invention is that one end of the graft-polymerized polyamide during the reaction or after the reaction is always a carboxyl group. It can be used as a new ionomer by neutralization and ionic crosslinking.

The polyolefin having a carboxyl group and/or an acid anhydride group used in the present invention may be a copolymer of an α-olefin and an unsaturated carboxylic acid such as acrylic acid or methacrylic acid or an unsaturated carboxylic acid anhydride, or a polyolefin with an unsaturated Examples include copolymers obtained by grafting or block polymerization of carboxylic acids or unsaturated carboxylic acid anhydrides, and modified polyolefins obtained by carboxylation reactions of polyolefins. Preference is given to using copolymers of carboxylic acids or unsaturated carboxylic anhydrides. Furthermore, the polyolefin having a carboxyl group or the like may contain other comonomers such as acrylic ester, methacrylic ester, vinyl acetate, and the like.

As the lactam in the present invention, any polymerizable lactam can be used, and caprolactam, lauryllactam, etc. are preferably used industrially. It is not necessary to use only one type of lactam, and a mixture of several types may be used.

In this case, the copolyamide will undergo graft polymerization.

Examples of the phosphorus compounds used in the present invention include orthophosphoric acid, phosphorous acid, metaphosphoric acid, pyrophosphoric acid, polyphosphoric acid, acid salts thereof, phosphorus pentoxide, phosphoric acid ester, phosphorous ester, etc., and organic phosphorous compounds include: Examples include triphenylphosphite and trisnonylphenylphosphite.

The amount of phosphorus compound added is 0 to 100 parts by weight of lactam.
．． 00Ql to 2 parts by weight is preferred. The phosphorus compound may be added from the beginning of the polymerization, or may be added during the polymerization.

Since the lactam is cationically polymerized in the present invention, it is not necessary to hydrolyze it, and therefore water is not required during polymerization, but there is no need to particularly carefully remove water when carrying out the present invention.

In the case of lactam or caprolactam, the reaction is slow if the concentration of carboxyl groups in the olefin is 1.3 equivalents/kg or less, so it is preferably 1.3 equivalents/kg or more, more preferably 1.5 equivalents/kg or more. It is. When the lactam is lauryl lactam, it is preferable from the viewpoint of reaction rate that the concentration of carboxyl groups in the olefin is 0.5 equivalent/kg or more.

When the graft copolymer according to the present invention is neutralized with metal ions, the metal ions include sodium ions, zinc ions, and other polyvalent metal ions.

(Effects of the invention) The polymerization method of the present invention not only provides a high grafting rate, but also does not require high pressure because it does not require the addition of water, and does not generate condensed water, so it is not necessary to consider water removal. It is very easy to implement.

(Effects of the Invention) The copolyamide resin polymerized according to the present invention has properties that compensate for the drawbacks of polyolefins and polyamides, so it can be widely used. Specifically, when the graft polymerized polyamide is a homopolyamide, it has a high melting point;
It also has low hygroscopicity and flexibility, so it can be used as a thermoplastic elastomer. Further, when the polyamide is a copolymer, it has a low melting point and can be used as a hot melt adhesive. Furthermore, the copolymers according to the invention can be used as compatibilizers for polyolefins and polyamides. Ionomers whose carboxyl groups are neutralized with metal ions can also be used for similar purposes.

(Example) The present invention will be explained below based on examples.

Example 1 Ethylene/methacrylic acid copolymer Nucrel 1525 (methacrylic acid content 15%) manufactured by Mitsui DuPont ■ 150 g
and 1g of caprolactam 150g and 75% phosphoric acid 0.5g
The mixture was placed in a separable flask and the atmosphere was purged with nitrogen, and polymerization was carried out at 280"C for 15 hours while stirring in nitrogen. Initially, it was a white, low-viscosity melt, but as the viscosity increased, it became transparent, and finally became a high-viscosity, transparent melt. A copolymer was obtained from which 6
When unreacted caprolactam was extracted with acetone at 0"C, the extraction loss was 9.1%. When the copolymer after monomer extraction was extracted with formic acid at 95°C for 6 hours, the extraction loss was 5.7%.
%Met. Therefore, the grafting ratio of caprolactam graph-polymerized to polyolefin was 71.4% with respect to the total amount of caprolactam monomers charged. In the polymerization of polycaprolactam, monomer always remains thermodynamically, but after excluding the residual monomer, the grafting ratio of the polymerized caprolactam grafted onto the polyolefin is 87.
It is 3%. In addition, when the formic acid extraction residue was analyzed for nitrogen, 4.
It was 5%.

Comparative Example 1 The same Mitsui DuPont Kansei Co., Ltd. tyrene used in Example 1 was used.
Methacrylic acid copolymer nucleol 1525150g, caprolactam 135g and ε-aminocaproic acid 17.4g
g was polymerized under nitrogen flow. The white, low-viscosity melt increased in viscosity while generating bubbles due to condensation, but remained white even after 5 hours of polymerization.

The acetone extraction amount of the obtained polymer was 10.5%,
The amount extracted with 95% formic acid was 33.1%. This is a grafting rate of 19.2% based on the total amount of caprolactam.
Grafting rate to polymerized caprolactam: 24.6%
That's what it means.

Comparative Example 2 500 g of ethylene/methacrylic acid copolymer Nucrel 1525 manufactured by Mitsui DuPont ■ used in Example 1, 500 g of caprolactam, and 5 g of water were placed in a 2 g autoclave, and after purging with nitrogen, the autoclave was sealed and heated at 260°C for 3 hours. After that, the pressure was gradually released at 240°C and the temperature was 30°C under nitrogen flow.
Time condensation was performed.

The obtained polymer was white, and the acetone extraction amount was 7.4%.
The amount of hot formic acid extracted was 33.7%. This means that the grafting rate is 22.8% with respect to the total charged caprolactam and 26.7% with respect to the polymerized caprolactam.

Example 2 150 g of ethylene/methacrylic acid copolymer Nucrel 1525 manufactured by DuPont Mitsui and 150 g of lauryl lactam
g and 0.5 g of phosphorus pentoxide in the same manner as in Example 1 at 280°C.
Polymerization was carried out for 3 hours. This system was transparent immediately after melting, and the viscosity increased while remaining transparent. When the obtained polymer was press-molded into a sheet with a thickness of 1 mm, a transparent sheet was obtained.

The melting point of this polymer according to differential calorimetry (DSC) is 157
It was ℃. On the other hand, the melting point of nylon 12 (polylauryllactam homopolymer) was measured at 178°C, so this copolymer had a melting point of 21°C compared to the homopolymer.
It can be seen that the melting point decreases.

Transparency suggests that a homogeneous graft polymer is produced, and a drop in melting point suggests that a copolymer that is not a homopolymer is produced. Moreover, the large melting point depression temperature suggests a high grafting rate. When this graft copolymer and nylon 12 were immersed in water at 60°C for 24 hours, the water absorption rate of this polymer was 1.13%, and that of nylon 12 was 1.13%.
It was 50%.

Comparative Example 3 150 g of ethylene/methacrylic acid copolymer Nucrel 1525 manufactured by DuPont Mitsui and 163.7 g of 12-aminododecanoic acid (equimolar amount to 500 g of lauryllactam)
was polymerized in a separable flask at 280° C. for 3 hours under nitrogen flow. The viscosity increased with the generation of bubbles due to condensation, but it remained opaque from beginning to end. This polymer remains opaque even when molded into a one-inch thick sheet, and has a melting point of 17.
The melting point was 1°C, which was 7°C lower than that of the homopolymer.

Comparative Example 4 Into a 2g autoclave, 1525500g of ethylene/methacrylic acid copolymer Nucrel manufactured by Mitsui DuPont ■, 500sr of lauryl lactam, and 15g of water were placed in a 2g autoclave and heated at 280°C.
The polymer obtained by heating for 1 hour, gradually releasing pressure at 240°C, and condensing for an additional 3 hours was opaque and had a melting point of 173°C.

Example 3 150 g of ethylene/methacrylic acid copolymer Nucrel 1525 manufactured by DuPont Mitsui, 75 g of lauryl lactam
1. 75 g of caprolactam, 75% phosphoric acid 1. Og was polymerized in the same manner as in Example 1 to obtain a transparent polymer. The amount of acetone extracted at 60°C was 5.1%. The melting point of the polymer after acetone extraction was 111°C, which was 29°C lower than the melting point of 140°C of a 50:50 caprolactam:lauryllactam copolymer, which was measured in the same manner.

Example 4 150 g of ternary copolymer of ethylene, methacrylic acid, and methacrylic acid ester Nucrel 0IO (methacrylic acid content 10%) manufactured by DuPont Mitsui and 150 g of lauryl lactam
and 1 g of triphenyl phosphite were polymerized in the same manner as in Example 1 to obtain a transparent and flexible polymer. The melting point was 161°C.

Example 5 Copolymer of ethylene and acrylic acid Niscor TR-5100 (acrylic acid content 11%) manufactured by Exxon Chemical Company 21
0 g of caprolactam, 90 g of caprolactam, and 0.3 g of 75% phosphoric acid were polymerized in the same manner as in Example 1. Acetone extraction amount is 4.2
%, and the amount of formic acid extracted was 3.1%. This means that the grafting rate is 76.1% with respect to the total charged caprolactam, and the grafting rate with respect to the polymerized caprolactam is 88.5%.

Example 6 Reactive oligomer MPX-101 manufactured by Kochu Kasei Kogyo Co., Ltd.
0 (copolymer of olefin and maleic anhydride, molecular weight 4
000, acid value 55) 150g and lauryllactam 150g
g and 0.5 g of 75% phosphoric acid were polymerized in the same manner as in Example 1 to obtain a brittle yellow transparent polymer. The melting point was 168°C.

Example 7 500 g of ethylene/methacrylic acid copolymer dinicrel 1050H (methacrylic acid content 10%) manufactured by DuPont Mitsui ■
and 500 g of lauryllactam and 0.5 g of 75% phosphoric acid.
Pour into a stainless steel container and heat at 280℃ for 5 hours after purging with nitrogen.
Polymerized for hours. The melt index (Ml) of the obtained polymer was 13.5 (190"C, 2160 g, The MI of the mixer was 9.5, and an increase in viscosity due to metal ion crosslinking was observed.

Example 8 The head of a 30 dragon φ twin screw extruder has an inner diameter of 200 mm and a length of 2 m.
A stainless steel pipe was attached, and a die for the strand was attached to the end of it. Inside this pipe, a static mixer manufactured by Sulzer was inserted on the extruder side, and a static mixer manufactured by Kenix was inserted on the die side. extruder,
The stainless steel pipe and die were kept at 280"C, the extruder inlet was sealed with nitrogen, and Nuclell 1050H, which was used in Example-5, was continuously fed to the extruder. About 4 hours after the start of feeding, the strands came out of the die. Next, a mixture of 60 parts by weight of ethylene/methacrylic acid copolymer Nucrel 1050H, 40 parts by weight of lauryl lactam, and 0.2 parts by weight of 75% phosphoric acid was continuously fed into the extruder, and after about 4 hours, the viscosity of the strands decreased. The copolymer was extruded rapidly.The strand was cooled and cut with a pelletizer to obtain a copolymer as a pellet.The pellet was transparent and had a melting point of 161°C.The pellet was molded into a test piece. When the physical properties were measured, the tensile strength was 450 kg/
cj, tensile elongation at break 320%, flexural modulus 3100k
g/C-.

Procedural amendment (voluntary) 1. Indication of the case Patent applicant Relationship to the Daicel-Hüls K.K. case Patent applicant Postal code 100 Address 3-8-1 Kasumigaseki, Chiyoda-ku, Tokyo
Name: Daicel-Hüls K.K.5, amended to the content of the amendment.

(2) Delete "(Effects of the invention)" in the third line of page 9.

Claims (2)

[Claims] (1) A method for producing a copolymerized polyamide resin in which a polyamide is graft-polymerized on a polyolefin chain, which comprises heating a polyolefin having a carboxyl group and/or an acid anhydride group and a lactam in the presence of a phosphorus compound. (2) A copolyamide resin obtained by neutralizing the copolymer obtained by the production method of claim 1 with metal ions.