CHAIN EXTENDER MASTERBATCH FOR PET EXTRUSION FOAMING, PREPARATION METHOD THEREFOR, AND USE THEREOF

Abstract

The present application relates to a chain extender masterbatch for PET extrusion foaming, preparation method therefor, and a use thereof. The masterbatch is mainly prepared by the following components in parts by weight: 5-30 parts of PMDA, 25-90 parts of PBT, 5-70 parts of POE+POE-g-GMA, in which POE accounts for 0-85% of POE+POE-g-GMA by weight; a melting temperature of PBT is 170-225° C. The preparation method includes melting and mixing the above components at a melting temperature of 180-230° C. and a screw speed of 100-500 rpm, and air cooling strand granulating or air cooling die face granulating. The masterbatch can be used in foaming processes of fiber grade PET, film grade PET, bottle grade PET, engineering plastic grade PET and recycled PET.

Claims

1. A chain extender masterbatch for polyethylene terephthalate (PET) extrusion foaming, comprising the following components in parts by weight: 5-30 parts of pyromellitic dianhydride (PMDA), 25-90 parts of polybutylene terephthalate (PBT), and 5-70 parts of polyolefin elastomer plus glycidyl methacrylate grafted polyolefin elastomer (POE+POE-g-GMA), wherein polyolefin elastomer (POE) accounts for 0-85% of the POE+POE-g-GMA by weight; and a melting temperature of the PBT is 170-225° C.

2. The chain extender masterbatch for PET extrusion foaming according to claim 1, comprising the following components in parts by weight: 10-20 parts of the PMDA, 50-80 parts of the PBT, and 10-35 parts of the POE+POE-g-GMA, wherein the POE accounts for 60-85% of the POE+POE-g-GMA by weight; and the melting temperature of the PBT is 175-215° C.

3. The chain extender masterbatch for PET extrusion foaming according to claim 1, wherein an intrinsic viscosity of the PBT is 0.75-1.3 dL/g.

4. The chain extender masterbatch for PET extrusion foaming according to claim 3, wherein the intrinsic viscosity of the PBT is 0.90-1.20 dL/g.

5. The chain extender masterbatch for PET extrusion foaming according to claim 1, wherein a melt flow rate of the POE is 0.5-5 g/10 min, and a melt flow rate of glycidyl methacrylate grafted polyolefin elastomer (POE-g-GMA) is 1-5 g/10 min.

6. The chain extender masterbatch for PET extrusion foaming according to claim 5, wherein the melt flow rate of the POE is 0.5-1.5 g/10 min, and the melt flow rate of the POE-g-GMA is 2-5 g/10 min.

7. The chain extender masterbatch for PET extrusion foaming according to claim 1, wherein a grafting ratio of glycidyl methacrylate (GMA) in glycidyl methacrylate grafted polyolefin elastomer (POE-g-GMA) is 0.2-5%.

8. The chain extender masterbatch for PET extrusion foaming according to claim 7, wherein the grafting ratio of the GMA in the POE-g-GMA is 0.5-2%.

9. A preparation method for the chain extender masterbatch for PET extrusion foaming according to claim 1, comprising the following steps: (1) weighing the following components in parts by weight: 5-30 parts of the PMDA, 25-90 parts of the PBT, and 5-70 parts of the POE+POE-g-GMA, wherein the POE accounts for 0-85% of the POE+POE-g-GMA; and (2) feeding above components into an extruder, mixing at a mixing temperature higher than a melting temperature of the PBT by 5-25° C. and lower than a melting temperature of a chain extender by 20-100° C. and a screw speed of 100-500 rpm, and granulating.

10. Use of the chain extender masterbatch for PET extrusion foaming according to claim 1 in a PET extrusion foaming process, with one or more PET raw materials selected from a group consisting of fiber grade PET, film grade PET, bottle grade PET, engineering plastic grade PET, and recycled PET, wherein an intrinsic viscosity of the PET is 0.5-1.5 dL/g, an end carboxyl group concentration of the PET is 15-50 mol/t, an amount of the chain extender masterbatch added in a process of PET extrusion foaming is 0.5-10 wt % by mass.

11. Use of a chain extender masterbatch for PET extrusion foaming prepared by the preparation method of the chain extender masterbatch for PET extrusion foaming according to claim 9 in a PET extrusion foaming process, with one or more PET raw materials selected from a group consisting of fiber grade PET, film grade PET, bottle grade PET, engineering plastic grade PET, and recycled PET, wherein an intrinsic viscosity of the PET is 0.5-1.5 dL/g, an end carboxyl group concentration of the PET is 15-50 mol/t, an amount of the chain extender masterbatch added in a process of PET extrusion foaming is 0.5-10 wt % by mass.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0033] FIG. 1 is a schematic diagram of the cell morphology of a sample of Application example 9.

[0034] FIG. 2 is an elongational rheological curve of a sample of Application example 9 under different elongational strain rate.

DETAILED DESCRIPTION

[0035] The present application is further described in detail below in combination with the FIGs.

[0036] PBT is available from Sinopec; POE is available from LG Chemical Company; POE-g-GMA is available from JiaYiRong Compatibilizer Co., Ltd.

Example 1

[0037] A chain extender masterbatch for PET extrusion foaming was prepared by the following steps:

(1) Batching: the following components in parts by weight were weighted: 5 parts of PMDA, 25 parts of PBT, 70 parts of POE-g-GMA. The melting temperature of PBT was 190° C., the intrinsic viscosity of PBT was 1.0 dL/g, the melt flow rate of POE-g-GMA was 2 g/10 min, and the grafting ratio of GMA in POE-g-GMA was 1%; and
(2) The above components were melted and mixed by a twin-screw extruder at 205° C. All components were fed from a main feeding port of the extruder, and subjected to melting, mixing and extrusion through a multi-hole extruder head. The screw diameter of the extruder D was 30 mm, and the length-diameter ratio L/D of the extruder screw was 30-48, which was 40 in this example. The screw speed was 100-500 rpm, which was 200 rpm in this example. The extruded material was air cooled and granulated as the chain extender masterbatch.

Example 2

[0038] A chain extender masterbatch for PET extrusion foaming was prepared by the following steps:

(1) Batching: the following components in parts by weight were weighted: 5 parts of PMDA, 25 parts of PBT, 35 parts of POE, and 35 parts of POE-g-GMA. The melting temperature of PBT was 190° C., the intrinsic viscosity of PBT was 1.0 dL/g, the melt flow rate of POE was 1 g/10 min, the melt flow rate of POE-g-GMA was 2 g/10 min, and the grafting ratio of GMA in POE-g-GMA was 1%; and
(2) The above components were melted and mixed by a twin-screw extruder. All components were fed from a main feeding port of the extruder. The screw diameter of the extruder D was 30 mm, and the length-diameter ratio L/D of the extruder screw was 48, the mixing temperature was 205° C., and the screw speed was 200 rpm. The extruded material was air cooled and granulated.

Example 3

[0039] A chain extender masterbatch for PET extrusion foaming was prepared by the following steps:

(1) Batching: the following components in parts by weight were weighted: 10 parts of PMDA, 40 parts of PBT, 30 parts of POE, and 20 parts of POE-g-GMA. The melting temperature of PBT was 190° C., the intrinsic viscosity of PBT was 1.0 dL/g, the melt flow rate of POE was 1 g/10 min and that of POE-g-GMA was 2 g/10 min, and the grafting ratio of GMA in POE-g-GMA was 1%; and
(2) The above components were melted and mixed by a twin-screw extruder. All components were fed from a main feeding port of the extruder. The screw diameter of the extruder D was 30 mm, the length-diameter ratio L/D of the extruder screw was 48, the mixing temperature was 205° C., and the screw speed was 200 rpm. The extruded material was air cooled and granulated.

Example 4

[0040] A chain extender masterbatch for PET extrusion foaming was prepared by the following steps:

(1) Batching: the following components in parts by weight were weighted: 10 parts of PMDA, 50 parts of PBT, 24 parts of POE, and 16 parts of POE-g-GMA. The melting temperature of PBT was 190° C., the intrinsic viscosity of PBT was 1.0 dL/g, the melt flow rate of POE was 1 g/10 min, the melt flow rate of POE-g-GMA was 2 g/10 min, and the grafting ratio of GMA in POE-g-GMA was 1%; and
(2) The above components were melted and mixed by a twin-screw extruder. All components were fed from a main feeding port of the extruder. The screw diameter of the extruder D was 30 mm, the length-diameter ratio L/D of the extruder screw was 48, the mixing temperature was 205° C., and the screw speed was 200 rpm. The extruded material was air cooled and granulated.

Example 5

[0041] A chain extender masterbatch for PET extrusion foaming was prepared by the following steps:

(1) Batching: the following components in parts by weight were weighted: 10 parts of PMDA, 60 parts of PBT, 18 parts of POE, and 12 parts of POE-g-GMA. The melting temperature of PBT was 190° C., the intrinsic viscosity of PBT was 1.0 dL/g, the melt flow rate of POE was 1 g/10 min, the melt flow rate of POE-g-GMA was 2 g/10 min, and the grafting ratio of GMA in POE-g-GMA was 1%; and
(2) The above components were melted and mixed by a twin-screw extruder. All components were fed from a main feeding port of the extruder. The screw diameter of the extruder D was 30 mm, the length-diameter ratio L/D of the extruder screw was 48, the mixing temperature was 205° C., and the screw speed was 200 rpm. The extruded material was air cooled and granulated.

Example 6

[0042] A chain extender masterbatch for PET extrusion foaming was prepared by the following steps:

(1) Batching: the following components in parts by weight were weighted: 10 parts of PMDA, 70 parts of PBT, 12 parts of POE, and 8 parts of POE-g-GMA. The melting temperature of PBT was 190° C., the intrinsic viscosity of PBT was 1.0 dL/g, the melt flow rate of POE was 1 g/10 min, the melt flow rate of POE-g-GMA was 2 g/10 min, and the grafting ratio of GMA in POE-g-GMA was 1%; and
(2) The above components were melted and mixed by a twin-screw extruder. All components were fed from a main feeding port of the extruder. The screw diameter of the extruder D was 30 mm, the length-diameter ratio L/D of the extruder screw was 48, the mixing temperature was 205° C., and the screw speed was 200 rpm. The extruded material was air cooled and granulated.

Example 7

[0043] A chain extender masterbatch for PET extrusion foaming was prepared by the following steps:

(1) Batching: the following components in parts by weight were weighted: 10 parts of PMDA, 80 parts of PBT, 6 parts of POE, and 4 parts of POE-g-GMA. The melting temperature of PBT was 190° C., the intrinsic viscosity of PBT was 1.0 dL/g, the melt flow rate of POE was 1 g/10 min, the melt flow rate of POE-g-GMA was 2 g/10 min, and the grafting ratio of GMA in POE-g-GMA was 1%; and
(2) The above components were melted and mixed by a twin-screw extruder. All components were fed from a main feeding port of the extruder. The screw diameter of the extruder D was 30 mm, the length-diameter ratio L/D of an extruder screw was 48, the mixing temperature was 205° C., and the screw speed was 200 rpm. The extruded material was air cooled and granulated.

Example 8

[0044] A chain extender masterbatch for PET extrusion foaming was prepared by the following steps:

(1) Batching: the following components in parts by weight were weighted: 15 parts of PMDA, 60 parts of PBT, 15 parts of POE, and 10 parts of POE-g-GMA. The melting temperature of PBT was 190° C., the intrinsic viscosity of PBT was 1.0 dL/g, the melt flow rate of POE was 1 g/10 min, the melt flow rate of POE-g-GMA was 2 g/10 min, and the grafting ratio of GMA in POE-g-GMA was 1%; and
(2) The above components were melted and mixed by a twin-screw extruder. All components were fed from a main feeding port of the extruder. The screw diameter of the extruder D was 30 mm, the length-diameter ratio L/D of the extruder screw was 48, the mixing temperature was 205° C., and the screw speed was 200 rpm. The extruded material was air cooled and granulated.

Example 9

[0045] A chain extender masterbatch for PET extrusion foaming was prepared by the following steps:

(1) Batching: the following components in parts by weight were weighted: 20 parts of PMDA, 60 parts of PBT, 12 parts of POE, and 8 parts of POE-g-GMA. The melting temperature of PBT was 190° C., the intrinsic viscosity of PBT was 1.0 dL/g, the melt flow rate of POE was 1 g/10 min, the melt flow rate of POE-g-GMA was 2 g/10 min, and the grafting ratio of GMA in POE-g-GMA was 1%; and
(2) The above components were melted and mixed by a twin-screw extruder. All components were fed from a main feeding port of the extruder. The screw diameter of the extruder D was 30 mm, the length-diameter ratio L/D of the extruder screw was 48, the mixing temperature was 205° C., and the screw speed was 200 rpm. The extruded material was air cooled and granulated.

Example 10

[0046] A chain extender masterbatch for PET extrusion foaming was prepared by the following steps:

(1) Batching: the following components in parts by weight were weighted: 30 parts of PMDA, 50 parts of PBT, 12 parts of POE, and 8 parts of POE-g-GMA. The melting temperature of PBT was 190° C., the intrinsic viscosity of PBT was 1.0 dL/g, the melt flow rate of POE was 1 g/10 min, the melt flow rate of POE-g-GMA was 2 g/10 min, and the grafting ratio of GMA in POE-g-GMA was 1%; and
(2) The above components were melted and mixed by a twin-screw extruder. All components were fed from a main feeding port of the extruder. The screw diameter of the extruder D was 30 mm, the length-diameter ratio L/D of the extruder screw was 48, the mixing temperature was 205° C., and the screw speed was 200 rpm. The extruded material was air cooled and granulated.

Example 11

[0047] The chain extender masterbatch for PET extrusion foaming of example 11 is same as example 9 except that PBT was prepared by the following steps:

(1) dimethyl terephthalate, 1,4-butanediol, tetrabutyl titanate, and cyclohexanedimethanol in a certain proportion were added into a polymerization reactor, and were heated to 180° C. under stirring at N.sub.2 atmosphere, for transesterification reaction for 1.5 hr, and a by-product methanol was distilled. The molar ratio of dimethyl terephthalate to diol (1,4-butanediol+cyclohexanedimethanol) was 1:1.2, the mole percentage of cyclohexanedimethanol in diol was 5%, and the concentration of tetrabutyl titanate was 650 ppm.
(2) The distillation unit was turned off, and a vacuum system was turned on, then the system pressure was decreased to lower than 100 Pa, and the reactor was heated rapidly to 250° C. under stirring for carrying out a polycondensation reaction for 1.5 hr; and
(3) the reaction was stopped, then the resultant material was subjected to water cooling, and granulating to obtain PBT. The melting temperature of the obtained PBT was 190° C. The preparation method had advantages of fast reaction speed, environmentally friendly by-products, and the obtained PBT got better dispersion and compatibility in PET system.

Example 12

[0048] The chain extender masterbatch for PET extrusion foaming in example 12 was same as Example 11 except that the mole percentage of cyclohexanedimethanol in diol was 10%, the melting temperature of the prepared PBT was 185° C., and the mixing temperature was 200° C. at mixing step.

Example 13

[0049] The chain extender masterbatch for PET extrusion foaming in example 13 was same as Example 11 except that a mole percentage of cyclohexanedimethanol in diol was 20%, the melting temperature of the prepared PBT was 176° C., and the mixing temperature was 190° C. at mixing step.

Application Example 1

[0050] PET foam board was prepared through PET extrusion foaming by a twin-screw extruder. The screw diameter D of the extruder was 75 mm, and the length-diameter ratio L/D of the extruder screw was 40. A static mixer and a multi-hole foaming die with a width of 610 mm and a thickness of 40 mm were successively installed downstream of the extruder. After exiting from the die, the extrudate was pulled into a calibration machine, thereby obtaining a foamed PET board with rectangular cross section.

[0051] Fiber grade PET (the intrinsic viscosity IV was 0.65 dL/g, and the end carboxyl group concentration was 25 mol/t) and the chain extender masterbatch prepared in Example 1 were used for extrusion foaming, in which PET needed to be dried at 165° C. for 4 h, the output of the twin-screw extruder was 100 kg/hr, the feeding rate of PET was 95.5 kg/hr, and the feeding rate of the chain extender masterbatch was 4.5 kg/hr. PET and the chain extender masterbatch were fed separately by a feeder, and a blowing agent can be supercritical fluid (such as CO.sub.2, N.sub.2), alkane (such as butane, cyclopentane, etc.), Freon, or mixture of two or more of above blowing agents. In this application example, cyclopentane was selected as the blowing agent, which was injected into the extruder at a rate of 3 kg/hr through an injection pump. The setting temperatures during the extrusion process were shown in the following table:

TABLE-US-00001 Extrusion section Temperature(° C.) Feeding section 260 Melting section 265-280 Mixing section 280-290 Metering section 260-280 Static mixer 260-280 Die 250-275
PET foam board with uniform cell and stable performance may be continuously and stably prepared by the above preparation process.

Application Example 2

[0052] The PET extrusion foamed board of Application example 2 was same as Application example 1 except that the chain extender masterbatch prepared in Example 2 was used.

Application Example 3

[0053] The PET extrusion foamed board of Application example 3 was same as Application example 1 except that the chain extender masterbatch prepared in Example 3 was used.

Application Example 4

[0054] The PET extrusion foamed board of Application example 4 was same as Application example 1 except that the chain extender masterbatch prepared in Example 4 was used.

Application Example 5

[0055] The PET extrusion foamed board of Application example 5 was same as Application example 1 except that the chain extender masterbatch prepared in Example 5 was used.

Application Example 6

[0056] The PET extrusion foamed board of Application example 6 was same as Application example 1 except that the chain extender masterbatch prepared in Example 6 was used.

Application Example 7

[0057] The PET extrusion foamed board of Application example 7 was same as Application example 1 except that the chain extender masterbatch prepared in Example 7 was used.

Application Example 8

[0058] The PET extrusion foamed board of Application example 8 was same as Application example 1 except that the chain extender masterbatch prepared in Example 8 was used.

Application Example 9

[0059] The PET extrusion foamed board of Application example 9 was same as Application example 1 except that the chain extender masterbatch prepared in Example 9 was used.

Application Example 10

[0060] The PET extrusion foamed board of Application example 10 was same as Application example 1 except that the chain extender masterbatch prepared in Example 10 was used.

Application Example 11

[0061] The PET extrusion foamed board of Application example 11 was same as Application example 1 except that the chain extender masterbatch prepared in Example 11 was used.

Application Example 12

[0062] The PET extrusion foamed board of Application example 12 was same as Application example 1 except that the chain extender masterbatch prepared in Example 12 was used.

Application Example 13

[0063] The PET extrusion foamed board of Application example 13 was same as Application example 1 except that the chain extender masterbatch prepared in Example 13 was used.

Application Example 14

[0064] The PET extrusion foamed board of Application example 14 was made from the granules prepared by recycling and granulating PET beverage bottles (the intrinsic viscosity IV was 0.68 dL/g, and the end carboxyl group concentration was 35 mol/t) and the chain extender masterbatch prepared in Example 9 by the same extrusion equipment and foaming process as in Application Example 1 for PET extrusion foaming, so that the PET foamed board with uniform cell structure was continuously and stably prepared.

Application Example 15

[0065] The PET extraction foamed board of Application example 15 was prepared by a tandem extruder for PET extrusion foaming. The first stage twin-screw extruder had a screw diameter D of 52 mm and a length-diameter ratio L/D of 40, and the second stage single screw extruder had a screw diameter D of 90 mm and a length-diameter ratio L/D of 24. A static mixer and a multi-hole foaming die with a width of 35 mm and a thickness of 20 mm were successively installed downstream of the extruder. After exiting from the die, the extrudate was pulled into a calibration machine, thereby obtaining a foamed PET board with rectangular cross section.

[0066] Bottle grade PET (the intrinsic viscosity IV was 0.8 dL/g, and the end carboxyl group concentration was 30 mol/t) and the chain extender masterbatch prepared in Example 9 were used for extrusion foaming, in which PET needed to be dried at 165° C. for 4 hr, the output of the twin-screw extruder was 60 kg/hr, the feeding rate of PET was 58.5 kg/hr, and the feeding rate of the chain extender masterbatch was 1.5 kg/hr. PET and the chain extender masterbatch were fed separately by a feeder. In the example. Supercritical CO.sub.2 was adopted as the blowing agent, which was injected into the extruder at a speed of 2.5 kg/hr through an injection pump. The temperatures during the extrusion process were shown in the following table:

TABLE-US-00002 Extrusion section Temperature(° C.) First stage/twin-screw extruder Feeding section 260 Melting section 265-280 Mixing section 280-290 Metering section 260-280 Second stage/single screw extruder 220-250 Static mixer 250-270 Die 250-265
PET foamed board with uniform cell may be continuously and stably prepared by the above preparation process.

Application Example 16

[0067] The PET extrusion foamed board of Application example 16 was prepared by the following steps:

(1) the chain extender masterbatch was prepared according to the steps in Example 9 except that the melting temperature of PBT was 170° C., and the mixing temperature was 185° C.; and
(2) the foamed board was prepared according to the steps in Application Example 1, in which the chain extender masterbatch prepared in step (1) was used.

Application Example 17

[0068] The PET extrusion foamed board of Application example 17 was same as Application example 16 except that the melting temperature of PBT was 175° C., and the mixing temperature was 190° C.

Application Example 18

[0069] The PET extrusion foamed board of Application example 18 was same as Application example 16 except that the melting temperature of PBT was 215° C., and the mixing temperature was 225° C.

Application Example 19

[0070] The PET extrusion foamed board of Application example 19 was same as Application example 16 except that the melting temperature of PBT was 225° C., and the mixing temperature was 230° C.

Application Example 20

[0071] The PET extrusion foamed board of Application example 20 was prepared by the following steps:

(1) the chain extender masterbatch was prepared according to the steps in Example 9 except that the intrinsic viscosity of PBT was 0.75 dL/g; and
(2) the foamed board was prepared according to the steps in Application example 1, in which the chain extender masterbatch prepared in step (1) was used.

Application Example 21

[0072] The PET extrusion foamed board of Application example 21 was same as Application example 20 except that the intrinsic viscosity of PBT was 0.9 dL/g.

Application Example 22

[0073] The PET extrusion foamed board of Application example 22 was same as Application example 20 except that the intrinsic viscosity of PBT was 1.2 dL/g.

Application Example 23

[0074] The PET extrusion foamed board of Application example 23 was same as Application example 20 except that the intrinsic viscosity of PBT was 1.3 dL/g.

Application Example 24

[0075] The PET extrusion foamed board of Application example 24 was same as Application example 9 except that the grafting ratio of GMA in POE-g-GMA was 0.2%.

Application Example 25

[0076] The PET extrusion foamed board of Application example 25 was same as Application example 24 except that the grafting ratio of GMA in POE-g-GMA was 0.5%.

Application Example 26

[0077] The PET extrusion foamed board of Application example 26 was same as Application example 24 except that the grafting ratio of GMA in POE-g-GMA was 2%.

Application Example 27

[0078] The PET extrusion foamed board of Application example 27 was same as Application example 24 except that the grafting ratio of GMA in POE-g-GMA was 5%.

Comparative Example 1

[0079] The PET extrusion foamed board of Comparative example 1 was prepared by the following steps:

(1) the chain extender masterbatch was prepared according to the steps of Example 9 except that the melting temperature of PBT was 165° C., and the mixing temperature was 180° C.; and
(2) the foamed board was prepared according to the steps of Application Example 1, in which the chain extender masterbatch prepared in step (1) was used.

Comparative Example 2

[0080] The PET extrusion foamed board of Comparative example 2 was prepared by the following steps:

(1) the chain extender masterbatch was prepared according to the steps of Example 9 except that the melting temperature of PBT was 230° C., and the mixing temperature was 240° C.; and
(2) the foamed board was prepared according to the steps of Application Example 1, in which the chain extender masterbatch prepared in step (1) was used.

Comparative Application Example 1

[0081] The PET extrusion foamed board of Comparative application example 1 was prepared by the following steps:

(1) the chain extender masterbatch was prepared according to the steps of Example 9 except that the intrinsic viscosity of PBT was 0.6 dL/g; and
(2) the foamed board was prepared according to the steps of Application example 1, in which the chain extender masterbatch prepared in step (1) was used.

Comparative Application Example 2

[0082] The PET extrusion foamed board of Comparative application example 2 was prepared by the following steps:

(1) the chain extender masterbatch was prepared according to the steps of Example 9 except that the intrinsic viscosity of PBT was 1.4 dL/g; and
(2) the foamed board was prepared according to the steps of Application example 1, in which the chain extender masterbatch prepared in step (1) was used.

Comparative Application Example 3

[0083] The PET extrusion foamed board of Comparative application example 3 was prepared by the following steps:

(1) the chain extender masterbatch was prepared according to the steps of Example 9 except that the melt flow rate of POE was 0.2 g/10 min, and the melt flow rate of POE-g-GMA was 0.5 g/10 min; and
(2) the foamed board was prepared according to the steps of Application example 1, in which the chain extender masterbatch prepared in step (1) was used.

Comparative Application Example 4

[0084] The PET extrusion foamed board of Comparative application example 4 was prepared by the following steps:

(1) the chain extender masterbatch was prepared according to the steps of Example 9 except that the melt flow rate of POE was 6 g/10 min, and the melt flow rate of POE-g-GMA was 6 g/10 min; and
(2) the foamed board was prepared according to the steps of Application example 1, in which the chain extender masterbatch prepared in step (1) was used.

Comparative Application Example 5

[0085] The PET extrusion foamed board of Comparative application example 5 was prepared by the following steps:

(1) the chain extender masterbatch was prepared according to the steps of Example 9 except that the grafting ratio of GMA in POE-g-GMA was 0.1%; and
(2) the foamed board was prepared according to the steps of Application example 1, in which the chain extender masterbatch prepared in step (1) was used.

Comparative Application Example 6

[0086] The PET extrusion foamed board of Comparative application example 6 was prepared by the following steps:

(1) the chain extender masterbatch was prepared according to the steps of Example 9 except that the grafting ratio of GMA in POE-g-GMA was 7%; and
(2) the foamed board was prepared according to the steps of Application example 1, in which the chain extender masterbatch prepared in step (1) was used.

[0087] Testing Methods

(1) Apparent density: the foamed boards of the application examples and comparative examples were tested according to ISO 845 standard for the apparent density;
(2) Tensile strength: the foamed boards of the application examples and comparative examples were tested according to ASTMC297 standard for the tensile strength;
(3) Compressive strength: the foamed boards of the application examples and comparative examples were tested according to ISO 844 standard for the compressive strength;
(4) Shear strength: the foamed boards of the application examples and comparative examples were tested according to ISO 1922 standard for the shear strength;
(5) Intrinsic viscosity: according to GB/T14190, solvent was a mixture of phenol and tetrachloroethane in a weight ratio of 1:1, and the testing temperature was 25±0.1° C.;
(6) Cell morphology: the sample of Application example 9 was observed by scanning electron microscope (SEM) with a magnification of 200; and
(7) Processing condition: the material delivering and extruder head pressure in the masterbatch preparation stage and PET foaming stage were observed.

[0088] Testing results were shown in the following table:

TABLE-US-00003 Apparent Tensile Compressive Shear Intrinsic density strength strength strength viscosity Samples (kg/m.sup.3) (MPa) (MPa) (MPa) (dL/g) Processing condition Application 100 ± 5 2.41 1.64 0.9 1.0 Masterbatch preparation example 1 stage: uniform dispersion; stable foaming material delivering and moderate extruder head pressure Application 2.41 1.64 0.9 1.0 Masterbatch preparation example 2 stage: uniform dispersion; stable foaming material delivering and moderate extruder head pressure Application 2.47 1.70 1.2 1.2 Masterbatch preparation example 3 stage: uniform dispersion; stable foaming material delivering and moderate extruder head pressure Application 2.48 1.72 1.2 1.2 Masterbatch preparation example 4 stage: uniform dispersion; stable foaming material delivering and moderate extruder head pressure Application 2.49 1.74 1.2 1.3 Masterbatch preparation example 5 stage: uniform dispersion; stable foaming material delivering and moderate extruder head pressure Application 2.50 1.77 1.3 1.3 Masterbatch preparation example 6 stage: uniform dispersion; stable foaming material delivering and moderate extruder head pressure Application 2.46 1.69 1.1 1.2 Masterbatch preparation example 7 stage: uniform dispersion; stable foaming material delivering and moderate extruder head pressure Application 2.53 1.79 1.3 1.4 Masterbatch preparation example 8 stage: uniform dispersion; stable foaming material delivering and moderate extruder head pressure Application 2.57 1.82 1.4 1.5 Masterbatch preparation example 9 stage: uniform dispersion; stable foaming material delivering and moderate extruder head pressure Application 2.55 1.78 1.3 1.4 Masterbatch preparation example 10 stage: uniform dispersion; stable foaming material delivering and moderate extruder head pressure Application 2.60 1.85 1.5 1.6 Masterbatch preparation example 11 stage: uniform dispersion; stable foaming material delivering and moderate extruder head pressure Application 2.63 1.87 1.6 1.7 Masterbatch preparation example 12 stage: uniform dispersion; stable foaming material delivering and moderate extruder head pressure Application 2.62 1.83 1.5 1.6 Masterbatch preparation example 13 stage: uniform dispersion; stable foaming material delivering and moderate extruder head pressure Application 2.56 1.78 1.3 1.5 Masterbatch preparation example 14 stage: uniform dispersion; stable foaming material delivering and moderate extruder head pressure Application 2.58 1.79 1.4 1.5 Masterbatch preparation example 15 stage: uniform dispersion; stable foaming material delivering and moderate extruder head pressure Application 2.48 1.72 1.2 1.2 Masterbatch preparation example 16 stage: uniform dispersion; stable foaming material delivering and moderate extruder head pressure Application 2.53 1.76 1.3 1.3 Masterbatch preparation example 17 stage: uniform dispersion; stable foaming material delivering and moderate extruder head pressure Application 2.55 1.81 1.3 1.4 Masterbatch preparation example 18 stage: uniform dispersion; stable foaming material delivering and moderate extruder head pressure Application 2.50 1.72 1.3 1.3 Masterbatch preparation example 19 stage: uniform dispersion; stable foaming material delivering and moderate extruder head pressure Application 2.53 1.73 1.2 1.3 Masterbatch preparation example 20 stage: uniform dispersion; stable foaming material delivering and moderate extruder head pressure Application 2.55 1.78 1.3 1.4 Masterbatch preparation example 21 stage: uniform dispersion; stable foaming material delivering and moderate extruder head pressure Application 2.55 1.79 1.3 1.4 Masterbatch preparation example 22 stage: uniform dispersion; stable foaming material delivering and moderate extruder head pressure Application 2.54 1.75 1.2 1.4 Masterbatch preparation example 23 stage: uniform dispersion; stable foaming material delivering and moderate extruder head pressure Application 2.53 1.74 1.3 1.3 Masterbatch preparation example 24 stage: uniform dispersion; stable foaming material delivering and moderate extruder head pressure Application 2.55 1.77 1.4 1.4 Masterbatch preparation example 25 stage: uniform dispersion; stable foaming material delivering and moderate extruder head pressure Application 2.55 1.78 1.4 1.4 Masterbatch preparation example 26 stage: uniform dispersion; stable foaming material delivering and moderate extruder head pressure Application 2.53 1.75 1.3 1.3 Masterbatch preparation example 27 stage: uniform dispersion; stable foaming material delivering and moderate extruder head pressure Comparative 2.25 1.51 0.7 1.0 Masterbatch preparation example 1 stage: uniform dispersion; stable foaming material delivering and moderate extruder head pressure Comparative 2.29 1.53 0.8 1.0 Masterbatch preparation example 2 stage: uniform dispersion; stable foaming material delivering and moderate extruder head pressure Comparative 2.47 1.70 1.1 1.0 Masterbatch preparation application stage: non-uniform example 1 dispersion; unstable foaming material delivering and moderate extruder head pressure Comparative 2.53 1.76 1.4 1.5 Masterbatch preparation application stage: uniform example 2 dispersion; stable foaming material delivering and moderate extruder head pressure Comparative 2.53 1.74 1.2 1.3 Masterbatch preparation application stage: uniform example 3 dispersion; not stable enough foaming material delivering and moderate extruder head pressure Comparative 2.54 1.76 1.3 1.4 Difficult to prepare application masterbatch; stable example 4 foaming material delivering and moderate extruder head pressure Comparative 2.49 1.71 1.2 1.3 Difficult to prepare application masterbatch; stable example 5 foaming material delivering and moderate extruder head pressure Comparative 2.51 1.76 1.3 1.4 Easy to prepare application masterbatch; uniform example 6 dispersion; not stable enough foaming material delivering; moderate extruder head pressure
It can be seen from the above table that, the PET foam boards prepared by each application example of the present application had high tensile strength, compressive strength and shear strength, and excellent mechanical properties. As can be seen that the chain extender masterbatches prepared in Examples 1-10 had both excellent dispersity and compatibility in PET foaming system, so that the masterbatch had excellent chain extension efficiency, thereby preparing the PET foam board with low density and excellent mechanical properties. In Examples 11-13, the PBT components were self-made, and the preparation method had advantages of fast reaction speed, environmentally friendly by-products, and the obtained PBT got better dispersion and compatibility in PET system. The details can be seen from the testing results of Application examples 11-13.

[0089] The foam board of Application example 9 had excellent mechanical property. The cell structure of the sample of Application example 9 was observed by SEM. It can be seen from FIG. 1, the sample of Application example 9 had uniform and stable cell, which was conducive to prepare the foamed board with low density and excellent mechanical properties. In addition, it can be seen from FIG. 2 that, the sample of Application example 9 had significant strain hardening effect under different elongational strain rates, which indicated that the melt strength of the PET materials was improved, and the masterbatch had higher chain extension efficiency.

[0090] In Application examples 11-13, using the self-made PBT in which cyclohexanedimethanol was used to replace part of 1,4-butanediol destroyed the regularity of PBT molecular chain. PBT components with different melting temperatures were prepared. It can be seen that from the testing results, the mechanical properties of Application examples 11-13 were better than that of Application examples 1-10, so it can be seen that a self-made PBT had batter dispersity in PET system, thereby the mechanical properties of the PET foamed boards can be further improved.

[0091] In Application examples 16-19, the melting temperatures of PBT were preferred at 175-215° C., then the mechanical property of PET was the best. In Application examples 20-23, the intrinsic viscosities of PBT were preferred at 0.9-1.2 dL/g, then the mechanical property of the PET extrusion foamed board was the best. In Application examples 24-27, the grafting ratios of GMA in POE-g-GMA were 0.9-1.2 dL/g, and mechanical property of PET extrusion foamed board was the best.

[0092] In Comparative examples 1-2, when the melting temperature of PBT was 165° C., PBT would undergo thermal decomposition during PET extrusion foaming, to reduce the chain extension efficiency of the masterbatch. When the melting temperature of PBT was 230° C., PBT would partially react with PMDA during the preparation process of masterbatch, which also can decrease the chain extension efficiency of the masterbatch, and thereby further significantly decreasing the mechanical properties of PET extrusion foamed boards.

[0093] In Comparative application examples 1-2, when the intrinsic viscosities of PBT was 0.6 dL/g, the masterbatch was difficult to prepare. The melt pressure at the extrusion die fluctuated greatly, and the raw material delivering was not stable enough during PET foaming process, which would eventually decrease the mechanical properties of the foamed boards. When the intrinsic viscosity of PBT was 1.4 dL/g, PBT was difficult to prepare and the energy consumption was high.

[0094] In Comparative application examples 3-4, when POE and POE-g-GMA had low melt flow rates, the masterbatch had poor dispersion in PET foaming system, and the foaming materials had not stable enough delivering, as a result, the mechanical properties of PET foamed boards will be affected. When POE and POE-g-GMA had high melt flow rates, an excessive fluidity caused overflow, as a result, the masterbatch was difficult to be granulated, and thereby finally affecting the mechanical properties of PET foamed boards.

[0095] In Comparative application examples 5-6, when the grafting ratio of GMA in POE-g-GMA was 0.1%, the particle spacing of rubber phases in PBT system was larger than the critical molecular spacing, which would make the masterbatch preparation difficult, and the brittle-ductile transition of the foamed board cannot be achieved. As the grafting rate of GMA in POE-g-GMA increased, the particle size of the rubber phase became smaller and the rubber phase was more uniformly dispersed. When the grafting rate of GMA in POE-g-GMA reached 7%, crosslinking is easy to occur in PET extrusion foaming system, which affects the stability of foaming material delivering.

[0096] The chain extender masterbatch in the present application can also be introduced other kinds of processing aids, such as heat stabilizers, nucleating agents, flame retardants, etc. The flame retardants included halogen, phosphorus and inorganic compounds. The nucleating agents included talc, nanoclay and silicon dioxide.

[0097] Apparatus used during the PET extrusion foaming process includes but not limited to a twin-screw extruder, and actually may adopt all forms of extrusion foaming units, such as a single-screw extruder, a twin-screw extruder and a tandem extruder (the first stage was a twin-screw extruder and the second stage was a single-screw extruder or both the first and second stages were single-screw extruders).

[0098] The above are preferred embodiments of the present application, which are not intended to limit the protection scope of the present application. Therefore, all equivalent changes made according to the structure, shape and principle of the present application should be within the protection scope of the present application.