CN101747600A - Method for preparing polyethylene terephthalate (PET) blend - Google Patents

Abstract

The invention discloses a preparation method of a polyethylene terephthalate (PET) blend. Glycidyl methacrylate (GMA) was used as graft monomer, and comonomer, initiator and crosslinking inhibitor were added to melt graft polyolefin elastomer (POE) on a twin-screw extruder to prepare Glycidyl methacrylate grafted polyolefin elastomer POE-g-(GMA-co-St) with higher grafting rate and better fluidity, the prepared POE-g-(GMA-co-St) Melt blending with PET can effectively improve the impact resistance of PET. The preparation method provided by the invention has low requirements on production equipment, high efficiency and is convenient for large-scale production, and the prepared high-impact PET blend maintains certain rigidity while having good impact performance.

Description

A kind of preparation method of polyethylene terephthalate blend

technical field

The invention relates to a preparation method of a polyethylene terephthalate blend, in particular to a method for preparing a high-impact polyethylene terephthalate blend using a multi-component melt grafting technique method.

Background technique

PET (polyethylene terephthalate) is a very important thermoplastic engineering plastic, with excellent mechanical properties, electrical properties, heat resistance, chemical corrosion resistance, etc., widely used in automobiles, electronics and food and other industries. However, unmodified PET has slow crystallization rate, poor molding processability and low impact strength, thus limiting its further application.

In order to improve the impact resistance of PET, a lot of research has been done on PET/functionalized elastomer blend system at home and abroad. Plastic Industry 200836(12): 17-20, China Plastics 200418(3): 20-22, Chinese Patent CN1238356A, JOURNALOF POLYMER RESEARCH 2005 12(5): 355-359 reported the use of maleic anhydride grafted ethylene-1- Octene copolymer (POE-g-MAH) to improve the impact resistance of PET. The addition of these functionalized elastomers can improve the impact resistance of PET, but at the same time reduce the rigidity of PET. This is because when the single-component MAH is melt-grafted with POE, it is easy to cross-link during the grafting process, and the performance of the graft is reduced. At the same time, due to the structural reasons of the monomer, the grafting activity is low and the grafting rate is not high. Therefore, The toughening effect of POE-g-MAH is not ideal.

Contents of the invention

The purpose of the present invention is to overcome the defects of the prior art, to provide a preparation method of polyethylene terephthalate blends, by grafting polyolefin elastomers with glycidyl methacrylate, to prepare highly resistant Punching polyethylene terephthalate improves the impact resistance of PET while maintaining other properties of PET as much as possible to obtain a high-impact PET blend with excellent comprehensive properties.

The invention aims at the defects existing in the current PET impact modifier POE grafting technology: the grafting rate is not high; macromolecules are easy to cross-link during the grafting process, and the performance of the graft is poor. Glycidyl methacrylate (GMA) with higher activity and less volatility is used as the grafting monomer, and styrene (St) is used as the grafting co-monomer, which greatly improves the grafting rate of the system; at the same time, triphenyl phosphite is added As a cross-linking inhibitor, TPP effectively inhibits the cross-linking of macromolecules, solves the problem of low POE grafting rate and easy cross-linking, and prepares glycidyl methacrylate with high grafting rate and good fluidity Ester grafted polyolefin elastomer POE-g-(GMA-co-St). The obtained POE-g-(GMA-co-St) and PET were blended and extruded through an extruder to obtain a high-impact PET blend.

The object of the invention is achieved through the following technical solutions:

A kind of preparation method of polyethylene terephthalate blend, comprises the steps:

(1) Mix polyolefin elastomer, initiator, glycidyl methacrylate, comonomer and cross-linking inhibitor uniformly, put them into extruder, and carry out melt grafting reaction at 100-200°C to obtain formazan Glycidyl acrylate grafted polyolefin elastomer;

The parts by weight of each component are as follows:

Polyolefin Elastomer 100

Glycidyl methacrylate 0.05～8

Comonomer 0.05～8

Initiator 0.02～0.5

Inhibiting cross-linking agent 0.02～2;

(2) After mixing the glycidyl methacrylate grafted polyolefin elastomer obtained above and polyethylene terephthalate evenly, extrude the mixture at 230-280°C for granulation and dry to obtain polyethylene terephthalate Ethylene glycol phthalate blends;

The glycidyl methacrylate grafted polyolefin elastomer accounts for 5-20% by weight of the mixture, and the polyethylene terephthalate accounts for 80-95% by weight of the mixture.

The polyolefin elastomer includes ethylene-1-octene copolymer, ethylene-1-butene copolymer and ethylene-1-hexene copolymer.

The reaction process described in step (1) is: melt grafting reaction is carried out in a twin-screw extruder at 100-200°C, the screw diameter is 35-45mm, the aspect ratio L/D is 30-50, and the rotating speed is 40-60r /min.

The comonomer is styrene, alpha-methylstyrene or methyl acrylate.

The initiator is a peroxide initiator.

The peroxide type initiator includes dicumyl peroxide, benzoyl peroxide or di-t-butyl peroxide.

The inhibitory crosslinking agent is triphenyl phosphite or dimethylformamide.

The extrusion granulation is carried out in a twin-screw extruder, the screw length-to-diameter ratio L/D is 30-50, and the rotation speed is 100-200r/min.

The glycidyl methacrylate grafted polyolefin elastomer is glycidyl methacrylate grafted ethylene-1-octene copolymer, glycidyl methacrylate grafted ethylene-1-butene copolymer or formaldehyde Glycidyl methacrylate is grafted with ethylene-1-hexene copolymer, wherein the grafting rate of glycidyl methacrylate is 0.3%-1.3%.

The process described in step (2) is: extrude the mixture in a twin-screw extruder at 230-280°C for granulation, the screw diameter is 35-45mm, the length-to-diameter ratio L/D is 30-50, and the rotation speed is 100-200r/ min.

Compared with the prior art, the present invention has the following advantages:

(1) The glycidyl methacrylate graft polyolefin elastomer used in the present invention adopts glycidyl methacrylate as a graft monomer, and compared with the traditional graft monomer maleic anhydride, the activity is higher and the toxicity Small and non-volatile. The use of co-grafting monomers and anti-crosslinking agents effectively reduces the occurrence of self-polymerization of glycidyl methacrylate and crosslinking of ethylene-octene copolymers. The glycidyl methacrylate grafted ethylene prepared by the present invention -Octene copolymer has high grafting rate and good fluidity.

(2) The high-impact polyethylene terephthalate prepared by grafting polyolefin elastomer with glycidyl methacrylate has good impact performance while maintaining a certain rigidity. When the amount of glycidyl methacrylate grafted polyolefin elastomer was 15%, the impact strength of the resulting impact-resistant polyethylene terephthalate was more than 5 times that of pure PET, while the tensile strength and flexural strength Only a slight drop.

(3) The preparation method used in the present invention has low requirements on production equipment, high efficiency, and is convenient for large-scale production.

Detailed ways

Example 1

Mix 100 parts of ethylene-1-octene copolymer (Mitsui TAFERM, DF610), 3 parts of glycidyl methacrylate, 3 parts of styrene, 0.15 parts of dicumyl peroxide, and 1 part of triphenyl phosphite Uniform, extruded by a twin-screw extruder, stretched, cooled, and pelletized to obtain a grafted product. The process parameters are: twin-screw extruder, diameter 36mm, aspect ratio L/D 40, speed: 55r/min; the temperature of each section of the extruder is: Section I: 100°C; Section II: 175°C; Section III Segment: 180°C, Segment IV: 180°C; Segment V: 180°C; Segment VI: 180°C; Segment VII: 175°C. The obtained glycidyl methacrylate grafted polyolefin elastomer has a graft rate of 0.93% and a melt index of 0.84g/10min.

After the obtained glycidyl methacrylate grafted polyolefin elasticity and PET are proportioned according to the formula (mass fraction) in Table 1, they are melt-extruded through a twin-screw extruder. The process parameters are: twin-screw extruder, diameter 40mm, The aspect ratio L/D is 38, and the rotation speed is 150r/min. The temperature of each section of the extruder is: I section: 235°C; II section: 245°C; III section: 250°C, IV section: 250°C; V section: 245°C; VI section: 245°C; VII section: 230°C , cooled, pelletized, and dried to obtain the polyethylene terephthalate blend of the present invention, which is injected into a standard spline on an injection molding machine, and the injection molding temperature is 230-250°C. Its physical properties are listed in Table 1.

Example 2

Mix 100 parts of ethylene-1-octene copolymer (Mitsui TAFERM, DF610), 5 parts of glycidyl methacrylate, 3 parts of styrene, 0.15 parts of dicumyl peroxide, and 1 part of triphenyl phosphite Uniform, extruded by a twin-screw extruder, stretched, cooled, and pelletized to obtain a grafted product. The process parameters are: twin-screw extruder, diameter 36mm, aspect ratio L/D 40, speed: 55r/min; the temperature of each section of the extruder is: Section I: 100°C; Section II: 175°C; Section III Segment: 180°C, Segment IV: 180°C; Segment V: 180°C; Segment VI: 180°C; Segment VII: 175°C. The obtained glycidyl methacrylate grafted polyolefin elastomer has a graft rate of 1.25% and a melt index of 0.65 g/10 min.

After the obtained glycidyl methacrylate grafted polyolefin elasticity and PET are proportioned according to the formula (mass fraction) in Table 1, they are melt-extruded through a twin-screw extruder. The process parameters are: twin-screw extruder, diameter 40mm, The aspect ratio L/D is 38,150r/min. The temperature of each section of the extruder is: I section: 235°C; II section: 245°C; III section: 250°C, IV section: 250°C; V section: 245°C; VI section: 245°C; VII section: 230°C , cooled, pelletized, and dried to obtain the polyethylene terephthalate blend of the present invention. Inject into standard splines on an injection molding machine, and the injection temperature is 230-250°C. Its physical properties are listed in Table 1.

Example 3

Mix 100 parts of ethylene-1-octene copolymer (Mitsui TAFERM, DF610), 5 parts of glycidyl methacrylate, 5 parts of styrene, 0.15 parts of dicumyl peroxide, and 1 part of triphenyl phosphite Uniform, extruded by a twin-screw extruder, stretched, cooled, and pelletized to obtain a grafted product. The process parameters are: twin-screw extruder, diameter 36mm, aspect ratio L/D 40, speed: 55r/min; the temperature of each section of the extruder is: Section I: 100°C; Section II: 175°C; Section III Segment: 180°C, Segment IV: 180°C; Segment V: 180°C; Segment VI: 180°C; Segment VII: 175°C. The obtained glycidyl methacrylate grafted polyolefin elastomer has a graft rate of 1.20% and a melt index of 0.70 g/10 min.

After the obtained glycidyl methacrylate grafted polyolefin elasticity and PET are proportioned according to the formula (mass fraction) in Table 1, they are melt-extruded through a twin-screw extruder. The process parameters are: twin-screw extruder, diameter 40mm, The aspect ratio L/D is 38,150r/min. The temperature of each section of the extruder is: I section: 235°C; II section: 245°C; III section: 250°C, IV section: 250°C; V section: 245°C; VI section: 245°C; VII section: 230°C , cooled, pelletized, and dried to obtain the polyethylene terephthalate blend of the present invention. Inject into standard splines on an injection molding machine, and the injection temperature is 230-250°C. Its physical properties are listed in Table 1.

Example 4

100 parts of ethylene-1-butene copolymer (ExxonMobil PX9071), 0.05 parts of glycidyl methacrylate, 3 parts of α-methylstyrene, 0.02 parts of dicumyl peroxide, 0.02 parts of phosphorous acid The triphenyl ester is fully mixed and evenly extruded by a twin-screw extruder, drawn, cooled, and pelletized to obtain a grafted product. The process parameters are: twin-screw extruder, diameter 36mm, length-to-diameter ratio L/D 40, speed: 60r/min; the temperature of each section of the extruder is: Section I: 100°C; Section II: 170°C; Section III Segment: 180°C, Segment IV: 180°C; Segment V: 180°C; Segment VI: 180°C; Segment VII: 175°C. The obtained glycidyl methacrylate grafted polyolefin elastomer had a graft rate of 0.3% and a melt index of 2.0 g/10 min.

After the obtained glycidyl methacrylate grafted polyolefin elasticity and PET are proportioned according to the formula (mass fraction) in Table 1, they are melt-extruded through a twin-screw extruder. The process parameters are: twin-screw extruder, diameter 40mm, The aspect ratio L/D is 38,150r/min. The temperature of each section of the extruder is: I section: 235°C; II section: 245°C; III section: 250°C, IV section: 250°C; V section: 245°C; VI section: 245°C; VII section: 230°C , cooled, pelletized, and dried to obtain the polyethylene terephthalate blend of the present invention. Inject into standard splines on an injection molding machine, and the injection temperature is 230-250°C. Its physical properties are listed in Table 1.

Example 5

100 parts of ethylene-1-hexene copolymer (ExxonMobil 8230), 8 parts of glycidyl methacrylate, 8 parts of methyl acrylate, 0.5 parts of benzoyl peroxide, 2 parts of dimethylformamide Mix thoroughly and evenly, extrude through a twin-screw extruder, draw strands, cool, and pelletize to obtain a grafted product. The process parameters are: twin-screw extruder, diameter 36mm, length-to-diameter ratio L/D 40, speed: 50r/min; the temperature of each section of the extruder is: Section I: 100°C; Section II: 170°C; Section III Segment: 180°C, Segment IV: 180°C; Segment V: 180°C; Segment VI: 180°C; Segment VII: 175°C. The obtained glycidyl methacrylate grafted polyolefin elastomer has a graft rate of 2.0% and a melt index of 0.30 g/10 min.

After the obtained glycidyl methacrylate grafted polyolefin elasticity and PET are proportioned according to the formula (mass fraction) in Table 1, they are melt-extruded through a twin-screw extruder. The process parameters are: twin-screw extruder, diameter 40mm, The aspect ratio L/D is 38,150r/min. The temperature of each section of the extruder is: I section: 235°C; II section: 245°C; III section: 250°C, IV section: 250°C; V section: 245°C; VI section: 245°C; VII section: 230°C , cooled, pelletized, and dried to obtain the polyethylene terephthalate blend of the present invention. Inject into standard splines on an injection molding machine, and the injection temperature is 230-250°C. Its physical properties are listed in Table 1.

Table 1

From the mechanical properties of PET blends in Table 1, it can be seen that the amount of glycidyl methacrylate grafted polyolefin elastomer has an effect on the impact strength of the blend system of PET and glycidyl methacrylate grafted polyolefin elastomer very big. With the increase of the amount of glycidyl methacrylate grafted polyolefin elastomer, the impact strength of the blend system was greatly improved, while the tensile strength and bending strength decreased slightly. When the amount of glycidyl methacrylate grafted polyolefin elastomer was 15%, the impact strength of the blend system was more than 5 times that of pure PET, and the glycidyl methacrylate grafted polyolefin elastomer played a very good role. With the effect of impact modification, impact-resistant ethylene terephthalate with excellent impact properties has been prepared.

Claims (9)

1. the preparation method of a polyethylene terephthalate blend is characterized in that comprising the steps:

(1) with polyolefin elastomer, initiator, glycidyl methacrylate, monomer and press down linking agent and mix altogether, drops in the forcing machine, react, make the glycidyl methacrylate graft polyolefin elastomer at 100～200 ℃;

The parts by weight of each component are as follows:

Polyolefin elastomer 100

Glycidyl methacrylate 0.05～8

Be total to monomer 0.05～8

Initiator 0.02～0.5

Press down linking agent 0.02～2;

(2) glycidyl methacrylate graft polyolefin elastomer and the polyethylene terephthalate that obtains mixed, the mixture that obtains obtains the polyethylene terephthalate blend by forcing machine after 230～280 ℃ of following extruding pelletizations, drying;

Described glycidyl methacrylate graft polyolefin elastomer accounts for 5～20% weight of mixture, and polyethylene terephthalate accounts for 80～95% weight of mixture.

2. preparation method according to claim 1 is characterized in that described polyolefin elastomer comprises ethene-1-octene copolymer, ethene-butene-1 copolymer or ethene-1-hexene copolymer.

3. preparation method according to claim 1 is characterized in that the screw diameter of the described forcing machine of step (1) is 35～45mm, and length-to-diameter ratio L/D is 30～50, and rotating speed is 40～60r/min.

4. preparation method according to claim 1 is characterized in that described monomer altogether is vinylbenzene, alpha-methyl styrene or methyl acrylate.

5. preparation method according to claim 1 is characterized in that described initiator is the peroxide type initiator.

6. preparation method according to claim 5 is characterized in that described peroxide type initiator comprises dicumyl peroxide, benzoyl peroxide or ditertiary butyl peroxide.

7. preparation method according to claim 1 is characterized in that described but linking agent is triphenyl phosphite or dimethyl formamide.

8. preparation method according to claim 1 is characterized in that described extruding pelletization is to carry out at twin screw extruder, and screw diameter is 35～45mm, and length-to-diameter ratio L/D is 30～50, rotating speed 100～200r/min.

9. preparation method according to claim 1, the percentage of grafting that it is characterized in that glycidyl methacrylate in the described glycidyl methacrylate graft polyolefin elastomer is 0.3%～1.3%.