PBT resin, its manufacturing method and use

Abstract

The present invention discloses a PBT resin containing terminal groups with an acylurea group structure, wherein the content of the terminal groups with the acylurea group structure in the PBT resin is 0.5 to 10 mol / t, and the content of terminal carboxyl groups in the PBT resin is 20 mol / t or less. The PBT resin of the present invention is end-capped with a carbodiimide-functional group-containing terminal-capping agent, and the content of terminal carboxyl groups is 20 mol / t or less, thereby obtaining a PBT having partial β-type crystals, and thereby exhibiting excellent mechanical properties.

Description

[Technical Field]

[0001] The present invention relates to the technical field of polymeric materials, and in particular to PBT resin, its manufacturing method and applications. [Background technology]

[0002] PBT is a high-performance engineering plastic with many advantages, including high mechanical strength, excellent fatigue resistance, good dimensional stability, and excellent solvent resistance, and is widely used in fields such as electronics, electrical engineering, automobiles, and home appliances.

[0003] PBT is a semi-crystalline polymer containing aromatic rings. Its crystallization process can be divided into two stages: crystal nucleation and crystal growth. Depending on the degree of chain folding, PBT has two crystalline forms: α and β, which correspond to the crimped and extended states of the -CH2- segments in the PBT molecular chain, respectively. Generally, α crystals are more likely to form under relaxed conditions, while β crystals are more likely to form under tension. β crystals have a relatively low melting point and can reduce processing temperatures to some extent. However, there are currently few techniques for controlling the formation of β crystals in melt-crystallized PBT, and the addition of specific complex nucleating agents is usually required. For example, the paper "Effect of Complex Nucleating Agents on the Crystallization Behavior of PBT" reported that the addition of a mixture of nucleating agents, dibenzyl sorbitol and sodium benzoate, can induce the formation of irregular β crystals in PBT materials. Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to provide a PBT resin that has excellent mechanical properties and from which β-type crystals can be obtained. [Means for solving the problem]

[0005] The present invention is achieved by the following technical solutions.

[0006] The PBT resin according to the present invention contains a terminal group having an acylurea group structure, the content of the terminal group having the acylurea group structure in the PBT resin is 0.5 to 10 mol / t, and the content of terminal carboxyl groups in the PBT resin is 20 mol / t or less, The structural formula of the PBT resin containing a terminal group having an acylurea group structure is as follows: [ka] In the formula, R1 is [ka] or [ka] where n is an integer equal to or greater than 1; R2 is H or [ka] and p is an integer equal to or greater than 1.

[0007] In the structural formula of the PBT resin, m represents the range of the numerical value of the content of repeating units of terephthalic acid and butylene glycol, and the average value of m may be 20-500.

[0008] Preferably, in PBT resin Terminal group having an acylurea group structure The content of terminal carboxyl groups in the PBT resin is 3 to 6 mol / t, and the content of terminal carboxyl groups in the PBT resin is 15 mol / t or less. Terminal group having an acylurea group structure The content is measured by 13C-NMR spectroscopy.

[0009] The intrinsic viscosity range of PBT resin is 0.650 to 1.280 dL / g The intrinsic viscosity is measured in accordance with Chinese national standard GB / T 14190-2008.

[0010] The aforementioned Terminal group having an acylurea group structureis derived from an arylcarbodiimide functional group-containing end-capping agent.

[0011] Optionally, said Aryl The structural formula of the carbodiimide functional group-containing end-capping agent is as follows: End-capping agent I: [ka] , molecular weight 362.3, or End-capping agent II: [ka] , or End-capping agent III: [ka] where a and b are both integers of 1 or greater.

[0012] The method for producing a PBT resin of the present invention involves extruding PBT and an arylcarbodiimide-functional group-containing end-capping agent according to a blending ratio using a twin-screw extruder to obtain a PBT resin. The screw temperature zones are divided into 10 zones, with the first zone having a temperature of 220 to 240°C, the second zone having a temperature of 230 to 245°C, the third zone having a temperature of 235 to 245°C, the fourth zone having a temperature of 235 to 250°C, the fifth zone having a temperature of 220 to 240°C, the sixth zone having a temperature of 220 to 240°C, the seventh zone having a temperature of 210 to 230°C, the eighth zone having a temperature of 200 to 220°C, the ninth zone having a temperature of 200 to 220°C, and the tenth zone having a temperature of 220 to 240°C. The screw length to diameter ratio is 32 to 40:1, and the screw rotation speed is 250 to 400 rpm. In the present invention, the amount of arylcarbodiimide functional group-containing end-capping agent required for the reaction is calculated based on the content of terminal carboxyl groups in the initial PBT resin raw material, and a PBT resin product having a specific number of terminal carboxyl groups and acylurea group-containing end groups is produced.

[0013] The PBT resin of the present invention is applicable to the field of electronic devices, and in particular to products such as connectors for electronic devices. [Effects of the Invention]

[0014] The present invention has the following beneficial effects:

[0015] The PBT resin of the present invention is end-capped with a carbodiimide functional group-containing end-capping agent and has a terminal carboxyl group content of 20 mol / t or less, thereby enabling the production of PBT partially having β-type crystals (ratio of 3.5 to 10%) and simultaneously exhibiting excellent mechanical properties. DETAILED DESCRIPTION OF THE INVENTION

[0016] The present invention will be described in detail below with reference to specific examples. The following examples are intended to help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any way. Those skilled in the art may make various modifications and improvements without departing from the spirit and scope of the present invention. All such modifications and improvements are within the scope of the present invention.

[0017] The origins of the raw materials used in the present invention are as follows. Arylcarbodiimide functional group-containing end-capping agents: end-capping agent I, end-capping agent II (a=4 to 5), and end-capping agent III (b=9 to 10) are commercially available products. End-capping agent I: StabIlIzer 7000 End-capping agent II: Stabaxol-P End-capping agent III: StabIlIzer 9000 Other end-capping agent A: dicyclohexylcarbodiimide Other end-capping agents B: Epoxy resin, CYD-011 The PBT commercial product was obtained from commercially available grades that met the required parameters of intrinsic viscosity and terminal carboxyl groups. PBT-A: Intrinsic viscosity 0.82 dL / g , Terminal carboxyl group content 26.4mol / t, PBT GX112 PBT-B: Intrinsic viscosity 0.98 dL / g , Terminal carboxyl group content 22.0 mol / t, PBT GX121 PBT-C: Intrinsic viscosity 1.05 dL / g , Terminal carboxyl group content 16.1mol / t, PBT GX122J

[0018] Examples and Comparisons example The PBT resin was produced using the following method. PBT and an end-capping agent were extruded in a twin-screw extruder according to the blending ratio to obtain the PBT resin. The screw temperature zones were divided into 10 zones as follows: the first zone temperature was 220-240°C, the second zone temperature was 230-245°C, the third zone temperature was 235-245°C, the fourth zone temperature was 235-250°C, the fifth zone temperature was 220-240°C, the sixth zone temperature was 220-240°C, the seventh zone temperature was 210-230°C, the eighth zone temperature was 200-220°C, the ninth zone temperature was 200-220°C, and the tenth zone temperature was 220-240°C. The screw length-to-diameter ratio was 32-40:1, and the screw rotation speed was 250-400 rpm.

[0019] The measurement methods for each item are as follows. (1) Terminal carboxyl group content: Measured in accordance with Chinese national standard GB / T 14190-2008. (2) β-crystal fraction: 5-10 mg of material was weighed and placed in an aluminum crucible to prepare a DSC sample. A NETZSCH DSC214 was used. The temperature program consisted of heating from 30°C to 300°C at a rate of 10°C / min, maintaining the temperature for 5 minutes to eliminate thermal history, then cooling to 30°C at a rate of 10°C / min, and then heating again at this rate to 300°C, using nitrogen as the protective gas. The melting peaks of the second heating curve were integrated, and the area of ​​the lower-temperature melting peak was designated s1, and the area of ​​the higher-temperature melting peak was designated s2. The β-crystal fraction was calculated as s1 / (s1+s2)*100%. (3) Tensile strength: Measurement was carried out in accordance with the Chinese national standard GB / T 1039-1992, and the tensile performance test was carried out using an electronic universal testing machine.

[0020] [Table 1]

[0021] From Examples 1 to 9 and Comparative Examples, it was found that when the content of terminal groups having an acylurea group structure and terminal carboxyl groups was within the range of the present invention, β-type crystals could be obtained and the tensile strength of the resin was higher. Furthermore, when the content of terminal groups having an acylurea group structure and terminal carboxyl groups was preferable, the proportion of β-type crystals was higher and the tensile strength was also higher.

[0022] [Table 2]

[0023] Comparative Examples 6 and 7 show that the desired proportion of β-type crystals could not be obtained when the terminal group did not have an aryl acylurea group structure, and the desired proportion was not achieved when an epoxy resin-based terminal blocking agent, which is commonly used for PBT, was used.

Claims

1. A PBT resin containing a terminal group having an acylurea group structure, wherein the content of the terminal group having the acylurea group structure in the PBT resin is 0.5 to 10 mol / t, and the content of terminal carboxyl groups in the PBT resin is 20 mol / t or less; The structural formula of the PBT resin containing a terminal group having an acylurea group structure is as follows: 【Chemistry 1】 In the formula, R １ teeth, 【Chemistry 2】 or 【Transformation 3】 and n is an integer of 1 or greater; R ２ is H or 【Chemistry 4】 and p is an integer of 1 or more.

2. 2. The PBT resin according to claim 1, wherein the content of terminal acylurea groups in the PBT resin is 3 to 6 mol / t, and the content of terminal carboxyl groups in the PBT resin is 15 mol / t or less.

3. 2. The PBT resin according to claim 1, wherein the intrinsic viscosity of the PBT resin is in the range of 0.650 to 1.

280.

4. 2. The PBT resin of claim 1, wherein the terminal acylurea groups are derived from an arylcarbodiimide functional group-containing end-capping agent.

5. The structural formula of the carbodiimide functional group-containing end-capping agent is: 【Transformation 5】 、 【change】 or 【change】 5. The PBT resin according to claim 4, wherein a and b are both integers of 1 or greater.

6. The method for producing the PBT resin according to any one of claims 1 to 5, wherein the PBT resin is obtained by extruding PBT and an arylcarbodiimide functional group-containing end-capping agent according to a blending ratio using a twin-screw extruder, wherein the screw temperature zones are set into 10 zones, with the first zone having a temperature of 220 to 240°C, the second zone having a temperature of 230 to 245°C, the third zone having a temperature of 235 to 245°C, and the fourth zone having a temperature of 240 to 250°C. the temperature of the fifth zone is 220-240°C, the temperature of the sixth zone is 220-240°C, the temperature of the seventh zone is 210-230°C, the temperature of the eighth zone is 200-220°C, the temperature of the ninth zone is 200-220°C, and the temperature of the tenth zone is 220-240°C; the length to diameter ratio of the screw is 32-40:1; and the screw rotation speed is 250-400 rpm.

7. Use of the PBT resin according to any one of claims 1 to 5, characterized in that it is used in the field of electronic equipment.

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