TWI439477B - Lactide-based acrylate-based copolymer - Google Patents

Description

Lactide-acrylate copolymer

The present invention relates to a novel lactide-acrylate copolymer, and more particularly to a lactide-acrylate copolymer obtained by reacting a lactide compound and an acrylate copolymer. The lactide-based compound is selected from the group consisting of D-lactide, L-lactide, meso-lactide, and mixtures thereof; and the lactide-acrylate copolymer of the present invention can be used as a thermoplasticity A resin, especially an impact-resistant modifier of polylactide.

Due to the problems caused by waste incineration and the continued consumption of land, the development of biodegradable polymers to replace petrochemical-based polymers that are not biodegradable is an important issue at present. Polylactide is a biodegradable polymer and its mechanical properties are also quite excellent. In addition to general life use, it can also be used for medical purposes, such as bone nails and sutures. Polylactide is decomposed by microorganisms and is attracting more and more attention from the viewpoints of environmental protection and renewable resources. Therefore, it is widely used in industrial or residential applications.

It is well known that polylactide polymers are unstable, and this instability is a disadvantage and an advantage. The advantage is that when it is biodegraded or otherwise lysed, it can greatly reduce its time. The disadvantage is that it is easy to crack during processing. This problem limits the commercial development of polylactide in place of conventional resins. Moreover, during the melt processing, polylactide may cause some side reactions due to cleavage, such as a decrease in molecular weight or an increase in the formation of lactide. Especially when operating at a high temperature above 230 °C, it is easier to accelerate the cracking of polylactide, so that polylactide should be in some It is more difficult to use.

The polymerization of polylactide is generally carried out by a ring-opening reaction starting from lactide, and then polymerized into a high molecular weight polylactide. The catalyst for ring-opening polymerization is generally Stannous Octoate (Sn(OCt) ₂ ). In addition, an alcohol (R-OH) can be used as a co-catalyst. In general, polylactide is a relatively brittle and poorly impact-resistant resin. Therefore, a well-known technique in which polylactide is melted with other resins to increase its impact strength has been known. However, the compatibility of these resins with polylactide melt mixing is poor, and the improvement in impact strength is also unsatisfactory. Therefore, various modifications of polylactide to improve its applicability are urgently studied in the industry.

The present invention is a novel lactide-acrylic copolymer (PLA-Acrylate copolymer) which is developed by solving the above problems, and is a lactide-based copolymer having a functional group. A ring opening reaction is carried out to form a novel lactide-acrylate copolymer. The novel lactide-acrylate copolymer can be subjected to an extension treatment to form a film or a sheet, and can also be kneaded with other thermoplastic resins. In particular, when the lactide-acrylate copolymer and the polylactide are kneaded, the compatibility is good, and the impact resistance of the polylactide can be greatly improved.

The lactide-acrylate copolymer of the present invention is mainly obtained by reacting 10 to 95 parts by weight of the lactide compound (A) and 5 to 90 parts by weight of the acrylate copolymer (B). Further, the lactide-based compound (A) is selected from the group consisting of D-lactide, L-lactide, meso-lactide, and a mixture thereof. The amount of the lactide-based compound (A) used is based on the lactide-based compound (A) and acrylic acid. The total amount of the ester copolymer (B) is 100 to 95 parts by weight, preferably 20 to 90 parts by weight, more preferably 30 to 85 parts by weight. When the amount of the lactide-based compound (A) used is less than 10 parts by weight, when the lactide-acrylate-based copolymer obtained as a reaction is used as an impact-resistant modifier of polylactide, the melt-kneaded phase The solubility is not good; if it exceeds 95 parts by weight, the effect of improving impact resistance is not satisfactory.

The acrylate-based copolymer (B) of the present invention is mainly obtained by copolymerization of a reactive functional group-containing ethylenic compound (b-1) and an acrylate-based monomer (b-2), and the acrylate-based monomer The glass transition temperature Tg when the body (b-2) is a homopolymer is less than 10 °C. The reactive functional group-containing ethylenic compound (b-1) is used in an amount of from 0.01 to 70% by weight, preferably from 0.05 to 50% by weight, more preferably from 0.1 to 30% by weight. When the reactive functional group-containing ethylenic compound (b-1) is used in an amount of less than 0.01% by weight, the lactide-acrylate copolymer obtained as a thermoplastic resin, particularly polylactide When the impact modifier is used, the compatibility and impact modification effect of the melt kneading are not good; if the reactive functional group-containing ethylenic compound (b-1) is used in an amount exceeding 70% by weight, the melt kneading is performed. The compatibility and impact resistance are poor.

The above reactive functional group-containing ethylenic compound (b-1) may be selected from a compound containing a hydroxyl group, an epoxy group, a carboxyl group, an amine group and an isocyanate group, wherein the acrylic acid is selected from a hydroxyl group-containing or epoxy group-containing group. An ester compound is preferred, and a hydroxyl group-containing acrylate compound is particularly preferred. The above hydroxyl group-containing acrylate compound may be selected, for example, from 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, acrylic acid. -3-hydroxypropyl ester, 3-hydroxypropyl methacrylate, propylene Acid-2-hydroxybutyl ester, 2-hydroxybutyl methacrylate, 3-hydroxybutyl acrylate, 3-hydroxybutyl methacrylate, 4-hydroxybutyl acrylate, methacrylic acid-4- Hydroxybutyl ester, dipropylene glycol acrylate, dipropylene glycol methacrylate, butanediol acrylate, butanediol methacrylate, polyethylene glycol methacrylate (polyethylene) Glycol methacrylate), polypropylene glycol acrylate, polypropylene glycol methacrylate, polyethylene glycol-polypropylene glycol methacrylate, polyethylene glycol -1,4-butylanediol methacrylate, caprolactone modified acrylate, caprolactone modified methacrylate ), 2-hydroxy-3-phenoxy-propyl acrylate, and the like. Among them, 2-hydroxy-3-phenoxypropyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 2-hydroxyethyl acrylate, methacrylic acid 2-Hydroxyethyl ester is preferred. These hydroxyl group-containing acrylate compounds may be used singly or in combination of two or more.

The above epoxy group-containing acrylate-based compound may be selected, for example, from glycidyl acrylate, glycidyl methacrylate, glycidyl α-ethyl acrylate, and glycidyl α-n-propyl acrylate. , α-n-butyl acrylate propyl acrylate, 3,4-butyl butyl acrylate, 3,4-butyl butyl methacrylate, 6,7-epoxyheptyl acrylate, 6,7-epoxyheptyl methacrylate, 6,7-epoxyheptyl α-ethyl acrylate, and the like. These epoxy group-containing acrylate compounds may be used singly or in combination of two or more.

The acrylate monomer (b-2) having a glass transition temperature Tg of less than 10 ° C in the above homopolymer may be selected, for example, from n-butyl acrylate, 2-ethylhexyl acrylate, isooctyl acrylate, or acrylic acid. Anthracene ester, isodecyl acrylate and dodecyl acrylate. By using such an acrylate-based monomer having a Tg of less than 10 ° C, a soft acrylate-based polymer can be obtained, which has an excellent effect on the improvement of impact resistance.

The acrylate-based copolymer (B) of the present invention may further contain 0 to 40% by weight of the other copolymerizable monomer (b-3), for example, a styrene-based monomer, an acrylonitrile-based monomer or the aforementioned acrylate-based single A (meth) acrylate monomer other than the body (b-2).

The acrylate-based copolymer (B) of the present invention may be melt-mixed with a hard acrylate-based polymer or copolymer having a high glass transition temperature Tg, and then subjected to ring-opening polymerization to a propionate in the presence of a catalyst. A lactide-acrylate copolymer.

When the acrylate-based copolymer having a functional group of the present invention is subjected to a ring-opening reaction with lactide, a suitable catalyst such as an oxide or a halide of a metal of the IV, V, and VIII of the periodic table may be added. Halogenide) or carboxylate, specifically, for example, antimony trioxide Sb ₂ O ₃ , antimony oxide (SnO), tin dichloride (SnCl ₂ ), stannous Octoate (Sn(OCt) ₂ ) The amount of the catalyst used depends on the reaction, and is usually preferably 0.001 to 1.5 parts by weight based on 100 parts by weight of the lactide. A suitable solvent may also be added during the polymerization reaction, the polymerization temperature is about 100 ° C to 200 ° C, and the polymerization time is about 15 minutes to 10 hours. The obtained lactide-acrylate copolymer-based main chain is an acrylate-based copolymer (B), and the reactive functional group contained in the acrylate-based copolymer (B) is reacted with lactide to polymerize. The polylactide branch, the lactide which is not reacted with the reactive functional group, is polymerized to form a free polylactide homopolymer. For example, when the functional group is a hydroxyl group, the hydroxyl group reacts with lactide to form a polylactide branch; when the functional group is an epoxy group, the acid or base contained in the reaction system causes the epoxy group to be opened and C The lactide reaction forms a polylactide branch.

The lactide-based compound (A) of the present invention is a lactide-based compound which does not contain lactic acid, such as D-lactide, L-lactide, meso-lactide or a mixture thereof, if lactic acid is used. However, it is impossible to react with a reactive functional group to form a copolymer of high molecular weight.

The molecular weight distribution of the lactide-acrylate copolymer of the present invention measured by gel permeation chromatography (GPC) is a bimodal distribution. The first peak molecular weight Mw1 of the peak of the double peak is 80,000 to 3 million, and the second peak molecular weight Mw2 is 8,000 to 300,000, especially the first peak molecular weight Mw1 is 100,000 to 2.5 million and the second peak molecular weight Mw2 is 1. 10,000 to 250,000 is preferred, especially the first peak molecular weight Mw1 is 150,000 to 2 million and the second peak molecular weight Mw2 is 15,000 to 200,000. Further, Mw1>Mw2, wherein Mw1/Mw2>2 is preferred, Mw1/Mw2>3 is preferred, and Mw1/Mw2>4 is optimal.

The lactide-acrylate copolymer of the present invention can be kneaded with other thermoplastic resin (C) to form a resin composition such as high impact polystyrene (HIPS) or acrylonitrile-butadiene-styrene resin ( ABS), acrylonitrile-propylene Rubber-denatured styrene resin such as acid rubber-styrene resin (AAS), acrylonitrile-(ethylene-propylene rubber)-styrene resin (AES), polystyrene (PS), styrene-acrylonitrile copolymer (AS), styrene-methyl methacrylate copolymer (MS), polymethyl methacrylate (PMMA), polylactide (PLA) (eg poly L-lactide, poly D-lactide, Poly-intermediate lactide and stereo complex-PLA), polycarbonate (PC), polyamine (PA), polyvinyl chloride (PVC), polybutylene terephthalate (PBT), polyethylene terephthalate (PET), etc., but not limited to these resins. In particular, the lactide-acrylate copolymer of the present invention has good compatibility with polylactide and can greatly improve the impact resistance of polylactide. The mixing ratio of the lactide-acrylate copolymer of the present invention to the other thermoplastic resin (C) is from 1 to 99/99 to 1, preferably from 2 to 60/98 to 40, more preferably from 3 to 3. 40/97~60.

The invention is described in the following examples, which are merely preferred embodiments of the present invention, and those skilled in the art should be modified or modified in accordance with the spirit of the present invention. Within the scope of the patent application of the present invention.

[Preparation of Acrylate Copolymer (B)] Acrylate copolymer (B1)

A 1000 ml flask equipped with a nitrogen inlet, a stirrer, a heater, a condenser and a thermometer was introduced into a 2-ethylhexyl acrylate (2-EHA) 99 g, 2-hydroxyethyl acrylate (HEMA for short) under a nitrogen atmosphere. ) 1g, 2,2'-azobis-2,4-dimethylvaleronitrile (2,2'-azobis-2,4- Dimethylvaleronitrile (abbreviated as ADVN) 2 g, α-methylstyrene dimer (abbreviated as α-MSD) 0.5 g and toluene 200 g, the reaction temperature in the polymerization process was maintained at 50 ° C, and the polymerization time was 6 hours. The resulting acrylate-based copolymer (B1) had a weight average molecular weight Mw of 290,000 as measured by gel permeation chromatography.

Acrylate copolymer (B1)~(B12)

The difference from the foregoing operation method is that the type and amount of the monomer for polymerization are changed, and after the polymerization is completed, the acrylate copolymer (B2) to (B12) formed is measured by gel permeation chromatography. The weight average molecular weight Mw is shown in Table 1.

[Example of lactide-acrylate copolymer] Example 1

33.3 g of the acrylate-based copolymer (B1) was vacuum-dried at 130 ° C for 3 hours, and dried to weigh 13.32 g. 13.32 g (10% by weight) of the acrylate copolymer (B1) after drying and 120 g (90% by weight) of L-lactide and ₂ 0.008 g of catalyst Sn (OCt) at 170 ° C for 6 hours. . After the reaction, a lactide-acrylate copolymer can be obtained, which is determined by a gel permeation chromatography method, and the obtained GPC chart shows that the molecular weight is a bimodal distribution, and the first peak molecular weight of the bimodal peak is Mw1. It is 1.1 million, the second peak molecular weight Mw2 is 90,000, and Mw1/Mw2 is 12.2.

Example 2~13

The operation method of the first embodiment is different from changing the type and amount of the acrylate copolymer, and the lactide-acrylate copolymer obtained after the polymerization is completed, and the gel permeation chromatography method is used. Determination, obtained The values of the first peak molecular weight Mw1, the second peak molecular weight Mw2, and Mw1/Mw2 are shown in Table 2.

[Application Examples of Lactide-Acrylate Copolymer]

100 parts by weight of poly L-lactide (Mw 170,000) as shown in Table 3, and the types and amounts of lactide-acrylate copolymers of Examples 8, 10, 11, 12, etc., respectively, as kneading machines (Kneader) was kneaded, pulverized and formed into test pieces, and tested for IZOD and FDI impact strength. The results are shown in Table 3.

Comparative example 1

The operation method of the first embodiment with the lactide-acrylate copolymer, except that the acrylate copolymer (B8) is used, and the lactide-acrylate copolymer obtained after the polymerization is completed will It was measured by gel permeation chromatography, and the first peak molecular weight Mw1 was 280,000, the second peak molecular weight Mw2 was 80,000, and Mw1/Mw2 was 3.5.

The acrylate-based copolymer (B8) used in Comparative Example 1 is an acrylate-based copolymer containing no hydroxyl group, and cannot react with L-lactide to form a lactide-acrylate copolymer.

100 parts by weight of poly L-lactide (Mw 170,000) and 10 parts by weight of the lactide-acrylate copolymer of Comparative Example 1 were kneaded by a kneader, pulverized, and then formed into test pieces, and The IZOD and FDI impact strengths were tested and the results are shown in Table 3.

Comparative example 2

The operation method of the same as the lactide-acrylate copolymer of Example 1, except that the acrylate-based copolymer (B11) 26.64 g (20% by weight) and L-lactide 106.68 g (80% by weight) ), the catalyst Sn(OCt) ₂ 0.008g was reacted at 170 ° C for 6 hours. The lactide-acrylate copolymer obtained after the completion of the polymerization was measured by a gel permeation chromatography method, and the first peak molecular weight Mw1 was found to be 600,000, and the second peak molecular weight Mw2 was 15,000, Mw1/Mw2. Is 40.

100 parts by weight of poly L-lactide (Mw 170,000) and 10 parts by weight of the lactide-acrylate copolymer of Comparative Example 2 were kneaded by a kneader, pulverized, and then injection molded to prepare a test piece. The IZOD and FDI impact strengths were tested and the results are shown in Table 3.

Comparative example 3

The operation method of the same as the lactide-acrylate copolymer of Example 1, except that the acrylate-based copolymer (B11) was 26.64 g (20% by weight) and the L-lactic acid was 106.68 g (80% by weight). The catalyst Sn(OCt) ₂ 0.008g was reacted at 170 ° C for 6 hours, and the obtained polymer solution was in a state where the concentration was thin, and the obtained polylactide had a weight average molecular weight of 5,000 or less, which was low in practicability.

Comparative example 4

The operation method of the same as the lactide-acrylate copolymer of Example 1, except that the acrylate-based copolymer (B3) was 26.64 g (20% by weight) and the L-lactic acid was 106.68 g (80% by weight). The catalyst Sn(OCt) ₂ 0.008g was reacted at 170 ° C for 6 hours, and the obtained polymer solution was in a state where the concentration was thin, and the obtained polylactide had a weight average molecular weight of 5,000 or less, which was low in practicability.

【test methods】

1. Determination of the first peak molecular weight Mw1 and the second peak molecular weight Mw2 of the peak of the bimodal molecular weight distribution: according to the gel permeation chromatography (GPC) of the Waters Company, and determined according to the following conditions: Column: KD- 806M

Detector: Water RI-410, UV-486

Mobile phase: THF (flow rate 1.0 c.c./min)

Standard molecular weight polystyrene as the measurement standard

2. Impact resistance (IZOD): Measured according to ASTM-D-256 (1/4° thick test piece with a notch at 23 ° C), unit: kg-cm/cm.

3. Drop hammer impact strength (FDI): The maximum height at which the test piece did not break under a 2 kg load was measured by a drop weight impact strength tester manufactured by TOYOSEIKI.

Test piece specifications: thickness 1/8", diameter 55mm injection molding disc unit: mm

HEMA: 2-hydroxyethyl acrylate GMA: glycidyl methacrylate 2-EHA: 2-ethylhexyl acrylate n-BA: n-butyl acrylate SM: styrene

Claims (16)

a lactide-acrylate copolymer obtained by reacting 45 to 90 parts by weight of a lactide compound (A) and 10 to 55 parts by weight of an acrylate copolymer (B); The lactide-based compound (A) is a compound which does not contain lactic acid, and the acrylate-based copolymer (B) is mainly composed of a reactive functional group-containing ethylenic compound (b-1) and an acrylate-based monomer (b-2). The acrylate-based copolymer (B) is composed of a reactive functional group-containing ethylenic compound (b-1) of 0.01 to 70% by weight and an acrylate-based monomer (b-2) of 99.99. An acrylate-based monomer having a glass transition temperature Tg of less than 10 ° C when the acrylate-based monomer (b-2) is a homopolymer is obtained by copolymerization of 30% by weight. The lactide-acrylate copolymer according to the first aspect of the invention, wherein the acrylate copolymer (B) is a reactive compound-containing ethylenic compound (b-1) 0.05 to 50 The weight % and the acrylate monomer (b-1) are 99.95 to 50% by weight copolymerized. The lactide-acrylate copolymer according to claim 2, wherein the acrylate-based copolymer (B) is composed of a reactive functional group-containing ethylenic compound (b-1) 0.1 to 30 The weight % and the acrylate monomer (b-2) are 99.9 to 70% by weight copolymerized. The lactide-acrylate copolymer according to claim 1, wherein the reactive functional group-containing ethylenic compound (b-1) is selected from a hydroxyl group-containing or epoxy group-containing acrylate system. Compound. The lactide-acrylate copolymer according to claim 1, wherein the acrylate monomer (b-2) is selected from the group consisting of acrylic acid- Butyl ester, 2-ethylhexyl acrylate, isooctyl acrylate, isodecyl acrylate, isodecyl acrylate and dodecyl acrylate. The lactide-acrylate copolymer according to claim 1, wherein the acrylate copolymer (B) further contains 0 to 40% by weight of the other copolymerizable monomer (b-3). The lactide-acrylate copolymer according to claim 6, wherein the other copolymerizable monomer (b-3) is selected from the group consisting of a styrene monomer, an acrylic monomer, or an acrylic acid. A (meth) acrylate monomer other than the ester monomer (b-2). The lactide-acrylate copolymer according to claim 1, wherein the lactide compound (A) is 20 to 90 parts by weight and the acrylate copolymer (B) is 10 to 80 parts by weight. The reaction is obtained. The lactide-acrylate copolymer according to item 8 of the patent application, which is composed of 30 to 85 parts by weight of the lactide compound (A) and 15 to 70 parts by weight of the acrylate copolymer (B). The reaction is obtained. The lactide-acrylate copolymer according to claim 1, wherein the lactide compound (A) is selected from the group consisting of D-lactide, L-lactide, and mesopropane. Lactide and mixtures thereof. According to the lactide-acrylate copolymer of claim 1, the molecular weight distribution measured by gel permeation chromatography is a bimodal distribution, and the first peak molecular weight of the peak of the bimodal peak is Mw1. It is 80,000 to 3 million, and the second peak molecular weight Mw2 is 8,000 to 300,000, and Mw1>Mw2. According to claim 11 of the patent range of lactide-acrylic acid An ester copolymer in which Mw1/Mw2>2. A resin composition which is formed by a lactide-acrylate copolymer and a thermoplastic resin (C) according to any one of claims 1 to 12, wherein The mixing ratio by weight of the lactide-acrylate copolymer and the thermoplastic resin (C) is from 1 to 99/99 to 1. The resin composition according to claim 13, wherein the thermoplastic resin (C) is polylactide. The lactide-acrylate copolymer according to claim 1, wherein the polymerization temperature of the lactide compound (A) and the acrylate copolymer (B) is from 100 ° C to 200 ° C, and polymerization is carried out. The time is 15 minutes to 10 hours. A lactide-acrylate copolymer comprising: a lactide compound unit; an ethylenic compound unit; and an acrylate monomer unit, wherein the lactide compound unit, The total amount of the ethylenic compound unit and the acrylate monomer unit is 100 parts by weight, the content of the lactide compound unit is 45 to 90 parts by weight, and the content of the ethylenic compound unit is 0.001. 38.5 parts by weight, the content of the acrylate monomer unit is 3 to 54.995 parts by weight, the lactide-acrylate copolymer is a bimodal molecular weight distribution, and the bimodal molecular weight includes a first peak molecular weight Mw1 And a second peak molecular weight Mw2, and 3 < Mw1/Mw2 < 25.