CN110564115B

CN110564115B - Antistatic polymer composition

Info

Publication number: CN110564115B
Application number: CN201910864020.6A
Authority: CN
Inventors: 苏润; 郁建飞
Original assignee: Nantong Xiexin Hot Melt Adhesive Co ltd
Current assignee: Nantong Xiexin Hot Melt Adhesive Co ltd
Priority date: 2019-09-12
Filing date: 2019-09-12
Publication date: 2022-03-15
Anticipated expiration: 2039-09-12
Also published as: CN110564115A

Abstract

The invention discloses an antistatic polymer composition, comprising: 50-94.2 wt% of at least one thermoplastic polyester resin with a glass transition temperature of more than 30 ℃, 0.8-15 wt% of at least one ether-segment-containing copolyester polymer with a glass transition temperature of less than 25 ℃ and 5-35 wt% of conductive filler, wherein the raw materials are obtained by blending and melting, then carrying out twin-screw extrusion molding and granulating, and the product is used for preparing plastic products such as electric/electronic components such as antistatic handles, containers or connectors and the like or automobile components. The invention selects the conductive materials with larger sizes such as carbon fiber and the like, keeps the continuity of a conductive path, the stability of the conductive performance of a product and a good reinforcing effect, has good compatibility of the copolyester polymer containing the ether segment and the thermoplastic polyester material, wide processing window and small negative influence on the mechanical performance, and the composition has low resistivity, high mechanical performance, good formability and good processing environment.

Description

Antistatic polymer composition

Technical Field

The invention belongs to the technical field of high molecular materials, and particularly relates to a polymer composition with improved antistatic property.

Background

Thermoplastic polymers such as polyester materials have excellent mechanical properties, moldability and chemical resistance, and thus have been used in automobile parts, electric/electronic parts and many other applications. In certain applications, it is desirable that these polymers also be antistatic or even conductive, and can generally be achieved by incorporating conductive additives such as carbon fibers, graphite, carbon black, and the like. However, these conductive additives are expensive, and when the amount of the conductive additives is high, the toughness (such as elongation at break) of the material is seriously affected. Therefore, there is a continuing need in the engineering to develop more efficient low resistance compositions to achieve low cost, high performance antistatic/conductive materials.

In view of the above problems, some studies on modification of polyamide have been made in the prior art, for example, chinese patent CN102850735B discloses a PBT/ASA composition having high conductivity, which can obtain relatively low resistance by using one or more of silicone powder, polyester terephthalate or peptide as a carbon nanotube dispersant. However, the carbon nanotubes are very expensive, and the masterbatch needs to be pre-dispersed, so the overall cost is still very high. Another chinese patent CN102532823B discloses a technical solution of adding multi-walled carbon nanotubes and epoxy elastomer to PBT to obtain an antistatic material, but the elastomer generally causes a decrease in strength modulus, and the combination with carbon nanotubes does not significantly reduce the system resistance. While the canadian patent CA1293367C has to use continuous carbon fibers in order to achieve high conductivity, resulting in great restrictions on processing conditions and low yields and practicality.

Disclosure of Invention

The invention provides an antistatic polymer composition with low resistance, high mechanical property and moderate cost aiming at the defects of the prior art.

In order to achieve the purpose, the invention adopts the following technical scheme:

the antistatic polymer composition of the present invention comprises:

a)50-94.2 wt.% of at least one thermoplastic polyester resin having a glass transition temperature of above 30 ℃;

b)0.8 to 15% by weight of at least one copolyester polymer containing ether segments and having a glass transition temperature below 25 ℃;

c)5-35 wt% of a conductive filler;

wherein the total weight percent of the composition totals 100 weight percent.

The thermoplastic polyester resin is selected from one or more of the following substances: polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), polyethylene terephthalate (PET), polybutylene terephthalate-1, 4-cyclohexanedimethanol (PBTG), polytrimethylene terephthalate-1, 4-cyclohexanedimethanol (PTTG), polyethylene terephthalate-1, 4-cyclohexanedimethanol (PETG), polybutylene naphthalate (PBN), polytrimethylene naphthalate (PTN), polyethylene naphthalate (PEN), or Polyarylate (PAR).

In a certain embodiment, the thermoplastic polyester resin is polybutylene terephthalate (PBT) and has a glass transition temperature (Tg) of 40 ℃.

The copolyester polymer containing ether segments comprises polyester and polyether segments; wherein the polyester is selected from one or more of the following: polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), polyethylene terephthalate (PET), polybutylene terephthalate-1, 4-cyclohexanedimethanol (PBTG), polytrimethylene terephthalate-1, 4-cyclohexanedimethanol (PTTG), polyethylene terephthalate-1, 4-cyclohexanedimethanol (PETG), or an aliphatic polyester; and/or the polyether segment is polyglycol with 2-16 carbon atoms and is selected from one or more of the following substances: polyethylene glycol (PEG), polypropylene glycol (PPDO), polytetramethylene glycol (PTMG), polypentylene glycol (PTMPD), polyhexamethylene glycol (PHDO), and polysuberyl glycol (PODO).

The copolyester polymer containing ether segments is: i) a copolymer of polybutylene terephthalate (PBT) and polytetramethylene ether glycol (PTMG) having a glass transition temperature (Tg) of 20 ℃, 94 wt.% of the polybutylene terephthalate (PBT) and 6 wt.% of the polytetramethylene ether glycol (PTMG) in the copolymer;

and/or ii) a copolymer of polybutylene terephthalate (PBT) and polytetramethylene ether glycol (PTMG) and having a glass transition temperature (Tg) of 0 ℃ wherein the polybutylene terephthalate (PBT) is 70 wt.% and the polytetramethylene ether glycol (PTMG) is 30 wt.%.

The conductive filler is selected from one or more of the following substances: carbon fibers, graphite flakes, metal wires or fibers or fiber sheets with surfaces subjected to conductive treatment;

and/or a mixture of the conductive filler and carbon black and/or carbon nanotube powder.

In one embodiment, the electrically conductive filler is chopped carbon fiber.

In a second aspect, the antistatic polymer composition is obtained by blending and melting raw materials, then carrying out twin-screw extrusion molding and dicing.

In a third aspect, a plastic article comprising the above antistatic polymer composition can be used as an electrical/electronic part or an automotive part, including but not limited to antistatic handles, containers, connectors, antistatic protective cases.

Compared with the prior art, the invention has the following beneficial effects:

the invention selects the conductive materials with larger size (non-nanometer level) such as carbon fiber, etc., which can keep the continuity of the conductive path, the stability of the conductive performance of the product and the good reinforcing effect as much as possible; the copolyester polymer containing ether segment has good compatibility with thermoplastic polyester material, wide processing window, small negative influence on mechanical property, low resistivity, high mechanical property, good moldability and good processing environment.

Detailed Description

The technical solution of the present invention is further explained below with reference to specific examples.

The following materials were used in the examples and comparative examples:

polybutylene terephthalate (PBT), a PBT resin obtained from the Catharanthus roseus Artificial resins plant (Taiwan, China), under the trade name of

1100, a crystallization temperature (Tc) of about 190 ℃, a melting temperature (Tm) of about 225 ℃ and a glass transition temperature (Tg) of 40 ℃.

Carbon fiber, carbon fiber obtained from Zoltek (U.S.A.), under the trade name Panex^TM35 chopped strand (Type-45) having a tensile strength of about 4000MPa and a density of about 1.8g/cm³The average diameter is about 7 μm and the average length is about 6 mm.

Copolyester polymer i, a polyester polyether copolymer resin from southbound synxin hot melt adhesive ltd, had a PBT block content of about 94 wt.%, a PTMG ether content of about 6 wt.%, a melting temperature (Tm) of about 115 ℃ and a glass transition temperature (Tg) of about 20 ℃.

Copolyester polymer ii, a polyester polyether copolymer resin from southbound synxin hot melt adhesive ltd, having a PBT block content of about 70 wt.%, a PTMG ether content of about 30 wt.%, a melting temperature (Tm) of about 105 ℃ and a glass transition temperature (Tg) of about 0 ℃.

The raw materials and compounding ratios of examples 1 to 4 and comparative examples 1 to 4 were as shown in table 1, and polymer compositions were prepared by mixing in a twin-screw extruder (L: D44, throughput setting 40kg/h), with a barrel temperature set at about 250 ℃ and a screw speed of about 300 rpm. After leaving the extruder, the mixed composition was cooled and cut into resin pellets, followed by drying overnight.

The dried resin pellets obtained in each example were injection-molded into a test board of 100X 1mm by means of an injection molding machine (clamping force 120T), and the melting temperature and the mold temperature were set to about 250 ℃ and about 60 ℃, respectively.

The test panels were vacuum sealed in plastic bags lined with aluminum foil to keep them in the dry-molded state until measured with an electrometer/high resistance meter to obtain surface resistivity.

TABLE 1

In summary, in comparative examples 3 and 5, the copolyester polymer itself is not effective in reducing the surface resistivity of the PBT material, which is reduced to 10 in the presence of carbon fibers (or other conductive fillers)⁶(comparative example 1), and the surface resistivity was further significantly reduced after addition of the copolyester polymer (as in examples 1-4), although the addition amount of the copolyester polymer was required to be 0.5% or more (the addition amount of 0.5% in comparative example 2 did not bring about an effective effect), the mechanical properties of the resulting polymer composition, such as tensile strength in table 1, were highly maintained and were not found to be significantly reduced by the addition of the copolyester polymer. However, if the copolyester polymer is added in a large amount (comparative example 4), the electrical resistance cannot be significantly reduced, but the mechanical properties are greatly reduced, because the copolyester polymer itself is a material with lower strength, and when the copolyester polymer is added in a small amount, the structural framework of the composite is not affected, but the negative effect is significant after the phase region volume ratio is significant.

Claims

1. Use of an antistatic polymer composition in electrical and electronic parts of antistatic handles, containers, connectors and antistatic protective casings or in automotive parts, characterized in that the antistatic polymer composition consists of the following raw materials in weight percent:

a) 83% by weightThe polybutylene terephthalate (PBT) is obtained from the Changchun artificial resin factory of Taiwan, China, and has a trade name of

1100, crystallization temperature (Tc) of 190 ℃, melting temperature (Tm) of 225 ℃, glass transition temperature (Tg) of 40 ℃;

b)4 wt.% of a PBT-polyether copolymer, from southbound synxin hot melt adhesive limited, with a PBT block content of 94 wt.%, a PTMG ether content of 6 wt.%, a Tm of 115 ℃ and a Tg of 20 ℃;

c) 13% by weight of carbon fibers from Zoltek, USA under the trade name Panex^TM35 chopped fiber Type-45, the tensile strength is 4000MPa, and the density is 1.8g/cm³Average diameter of 7 μm and average length of 6 mm;

the raw materials are obtained by melt extrusion molding, cutting into granules and drying overnight through a twin-screw extruder with L: D44 and the yield of 40kg/h under the conditions that the cylinder temperature is 250 ℃ and the screw speed is 300 rpm.