Glass fiber reinforced PBT material, its preparation method and application

Abstract

The application belongs to the technical field of PBT materials, and particularly discloses a glass fiber reinforced PBT material, a preparation method and application thereof. In the injection molding process, the glass fiber reinforced PBT material improves the hydrolysis resistance of PBT, and the hydrolysis resistant agent can absorb oligomers or small molecule substances generated by PBT or additives, so that the content of oligomers and small molecule substances in the system is reduced, and the mold fouling problem generated in the injection molding process is improved.

Description

TECHNICAL FIELD

[0001] The application belongs to PBT materials, and particularly relates to a glass fiber reinforced PBT material and a preparation method and application thereof. BACKGROUND

[0002] Polybutylene terephthalate (PBT) is a polyester prepared by polycondensation of terephthalic acid and 1,4-butanediol. PBT has good mechanical properties, thermal stability, easy molding and the like, and is widely used in the fields of automobiles, electronic appliances and the like. In order to increase the comprehensive performance of PBT materials, some antioxidants, flame retardants, lubricants and the like are added to the PBT materials. At the same time, because PBT generally has the defect of large shrinkage rate after molding, the industry generally improves the shrinkage rate and strength by auxiliary addition of fillers such as glass fibers, and the material is generally referred to as reinforced PBT material. Because PBT itself has an ester bond, the ester bond is prone to hydrolysis under high temperature and high humidity conditions, leading to ester bond rupture, and in this process, the self-catalytic effect of the terminal carboxyl group of PBT accelerates the degradation of PBT, resulting in a significant reduction in the mechanical strength of the material and affecting the normal use of the material. Therefore, it is generally necessary to add some hydrolysis-resistant agents to improve the hydrolysis resistance of the material.

[0003] PBT has a fast crystallization rate, so it is generally molded by injection molding. However, the temperature in the injection molding process is high, which not only accelerates the hydrolysis process of PBT to some extent, but also causes PBT or conventional hydrolysis-resistant agents to decompose into a large number of oligomers and small molecules. This phenomenon can cause more residues to be left on the mold during the injection molding process, resulting in serious mold fouling. In the continuous processing process, the mold surface needs to be cleaned regularly to remove the mold fouling, resulting in low production efficiency.

[0004] Therefore, there is still a need to continue to develop a reinforced PBT material that is resistant to hydrolysis and has low mold fouling. SUMMARY

[0005] In view of the problems of poor hydrolysis resistance of the PBT material and serious mold fouling during injection molding in the prior art, the application provides a glass fiber reinforced PBT material and a preparation method and application thereof.

[0006] To achieve the above-mentioned purpose, the following technical solutions are specifically included:

[0007] On the one hand, the application provides an application of a compound of general formula (I) as a hydrolysis-resistant agent in a glass fiber reinforced PBT material, and the compound of general formula (I) is as follows:

[0008]

[0009] X1, X2, X3, X4, X5 are each selected from any one of hydrogen atom, alkyl, alkoxy, halogen.

[0010] The compound of general formula (I) belongs to amide-based compounds in the injection molding process of the glass fiber reinforced PBT material, and as a hydrolysis resistant agent in the glass fiber reinforced PBT material, the amide group of the hydrolysis resistant agent is easy to react with the terminal carboxyl group of PBT, so that the terminal carboxyl group of PBT is capped, and the terminal carboxyl group in the material is consumed. Therefore, by reducing the proportion of terminal carboxyl group in the material, the hydrolysis resistance of PBT is improved, and at the same time the hydrolysis resistant agent can absorb oligomers or small molecule substances generated by PBT or additives, reduce the content of oligomers and small molecule substances in the system, and improve the mold fouling problem generated in the injection molding process.

[0011] Preferably, the compound of general formula (I) includes at least one of phenylpropenylamide, p-methyl cinnamic amide, trans-2,5-dimethoxycinnamic amide, and 4-chlorocinnamic amide.

[0012] A glass fiber reinforced PBT material includes the following raw material components by weight:

[0013] PBT resin 59-91 parts, glass fiber 14-32 parts, the hydrolysis resistant agent 0.7-2.6 parts, and the additive 0.1-2 parts.

[0014] Preferably, the glass fiber reinforced PBT material includes the following raw material components by weight: PBT resin 60-90 parts, glass fiber 15-30 parts, hydrolysis resistant agent 1-2.5 parts, and additive 0.5-1.6 parts.

[0015] Preferably, the mass percentage of PBT resin in the glass fiber reinforced PBT material is not less than 50%, preferably not less than 60%, and further preferably not less than 70%.

[0016] Preferably, the intrinsic viscosity of the PBT resin is 0.6-1 dL / g, and further preferably 0.7-0.8 dL / g. The intrinsic viscosity of the PBT resin can be 0.6, 0.7, 0.8, 0.9, 1.0 dL / g, etc., and specific point values between the above point values. Due to the limitation of the length and the consideration of simplicity, the present application does not exhaustively list the specific point values included in the range. The intrinsic viscosity of the PBT resin of the present application is detected by GB / T 14190-2017 method at 25℃. Below the intrinsic viscosity of the PBT resin described above, the glass fiber reinforced PBT material can maintain a low mold fouling quality and high hydrolysis resistance in the injection molding process.

[0017] Preferably, the glass fiber is short glass fiber.

[0018] Preferably, the average diameter of the glass fiber is 10-13 μm, and the diameter of the glass fiber can be 10, 11, 12, 13 μm, etc., and specific point values between the above point values, limited to the length and for the sake of simplicity, the present application will not be listed in the range of specific point values included.

[0019] The diameter of the glass fiber can be measured by a scanning electron microscope.

[0020] Preferably, the mass percentage of the glass fiber in the glass fiber reinforced PBT material is 15-30%, and can be 15%, 17%, 19%, 21%, 23%, 25%, 27%, 29%, 30%, etc., and specific point values between the above point values, limited to the length and for the sake of simplicity, the present application will not be listed in the range of specific point values included.

[0021] With the above content of the glass fiber, not only the reinforcing effect of the glass fiber can be maximized, but also the hydrolysis resistance of the material can be improved.

[0022] Preferably, the mass percentage of the hydrolysis resistant agent in the glass fiber reinforced PBT material is 1-2.5%, and further preferably the mass percentage of the hydrolysis resistant agent in the glass fiber reinforced PBT material is 1.5-2%, and can be 1%, 1.2%, 1.5%, 1.7%, 2%, 2.2%, 2.5%, etc., and specific point values between the above point values, limited to the length and for the sake of simplicity, the present application will not be listed in the range of specific point values included.

[0023] Preferably, the auxiliary agent includes an antioxidant and a lubricant.

[0024] Further preferably, the antioxidant includes at least one of tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid]pentaerythritol ester, pentaerythritol tetra(3-laurylthiopropionate), tris[2.4-di-tert-butylphenyl]phosphite; and the lubricant includes at least one of ethylene bis-stearamide, E wax, calcium stearate, pentaerythritol tetrastearate.

[0025] The preparation method of the glass fiber reinforced PBT material of the present application comprises the following steps: mixing PBT resin, hydrolysis resistant agent, auxiliary agent and glass fiber, and melting under light, and then extruding, granulating to obtain the glass fiber reinforced PBT material.

[0026] In the preparation of the glass fiber reinforced PBT material, the present application can improve the hydrolysis resistance of the material by preparing the glass fiber reinforced PBT material under light irradiation; on the other hand, the carbon-carbon double bond in the hydrolysis-resistant agent acrylamide group polymerizes itself to form a four-membered carbon ring macromolecule, increasing its molecular weight and making it more difficult to separate out during injection molding, thereby avoiding the problem of increased mold fouling caused by the separation of the hydrolysis-resistant agent.

[0027] Preferably, the temperature of the melting is 200-240℃, and the wavelength of the light irradiation is 250-320nm.

[0028] The present application also provides a glass fiber reinforced PBT material for use in the preparation of electronic appliances, particularly in the preparation of connectors and controllers in the electronic appliance industry.

[0029] Compared with the prior art, the present application has the following beneficial effects: the glass fiber reinforced PBT material of the present application can improve the hydrolysis resistance of PBT during injection molding, and the hydrolysis-resistant agent can absorb oligomers or small molecules generated by PBT or additives, thereby reducing the content of oligomers and small molecules in the system and improving the problem of mold fouling generated during injection molding. DETAILED DESCRIPTION

[0030] In order to better illustrate the purpose, technical solution and advantages of the present application, the present application will be further described below through specific examples. Unless otherwise specified, the test methods used in the examples and / or comparative examples are conventional methods; and unless otherwise specified, the materials, reagents, etc. used can be obtained from commercial channels. Unless otherwise specified, the component raw materials used in each example and comparative example of the present application are the same in each parallel experiment.

[0031] PBT resin 1: PBT GX110, intrinsic viscosity: 0.6dL / g, Yizheng Chemical Fibre;

[0032] PBT resin 2: PBT GX111, intrinsic viscosity: 0.7dL / g, Yizheng Chemical Fibre;

[0033] PBT resin 3: PBT GX121, intrinsic viscosity: 1.0dL / g, Yizheng Chemical Fibre;

[0034] The chemical structure of the hydrolysis-resistant agent is shown in the following formula I:

[0035]

[0036] X1, X2, X3, X4, X5 are each selected from any one of a hydrogen atom, an alkyl group, an alkoxy group, and a halogen.

[0037] Hydrolysis-resistant agent 1: phenylpropenylamide, Hefei Tianjian Chemical Co., Ltd.;

[0038] Hydrolysis-resistant agent 2: p-methyl cinnamic amide, Shanghai Maikelin Biochemical Technology Co., Ltd.;

[0039] Hydrolysis-resistant agent 3: trans-2,5-dimethoxycinnamic amide, Sigma-Aldrich;

[0040] Hydrolysis-resistant agent 4: 4-chlorocinnamic amide, Shanghai Huayuan Century Trading Co., Ltd.;

[0041] Small molecule capture agent: 3-phenyl-2-propenoic acid, Shanghai Jizhi Biochemical Technology Co., Ltd.;

[0042] Glass fiber 1: diameter 10 μm, ECS10-4.5-534AKF, Jushi Glass Fiber;

[0043] Glass fiber 2: diameter 11 μm, ECS11-4.5-534A, Jushi Glass Fiber;

[0044] Glass fiber 3: diameter 13 μm, ECS13-4.5-534A, Jushi Glass Fiber;

[0045] Antioxidant 1: SONOX 1010, Shandong Sanfeng;

[0046] Antioxidant 2: RIANOX 412S, Tianjin Li'an Long;

[0047] Lubricant: PETS-AP, Fa Ji.

[0048] Examples 1-15 and Comparative Examples 1-5

[0049] A method for preparing a glass fiber reinforced PBT material, comprising the following steps:

[0050] (1) According to the formula in Table 1-2, PBT resin, antioxidant and lubricant, and hydrolysis-resistant agent were weighed respectively, mixed uniformly, and then added to the extruder;

[0051] (2) Then, according to the formula in Table 1-2, glass fiber was added from the side of the extruder, and was fully melted and mixed uniformly, with a melting temperature of 200-240℃, and light with a wavelength of 280 nm was applied in the homogenization section of the extruder, and then was extruded and granulated to obtain a glass fiber reinforced PBT material.

[0052] Table 1

[0053]

[0054]

[0055] Table 2

[0056]

[0057] The glass fiber reinforced PBT materials prepared in the above examples and comparative examples were subjected to injection molding scale test and rapid forming effect test:

[0058] (1) Injection molding scale test: a metal steel sheet was placed at the exhaust port position of the mold, 200 continuous injections were made at 260℃, the scale on the metal sheet was collected and weighed, and the mass difference before and after the metal sheet was used to characterize the scale size; the smaller the mass difference, the less the scale.

[0059] (2) Hydrolysis resistance: the evaluation material was made into corresponding ISO standard sample, after being stored in 85℃, 85% R.H. humid heat environment for 500h, compared with the sample before test, the retention rate of tensile strength and notched impact strength of the evaluation sample after test was evaluated, wherein the tensile strength was tested according to the sample of ISO 527 1A-2019, and the test speed was 5mm / min; the notched impact strength was tested according to the sample of ISO 179 / 1eA, and the pendulum was 4J; the greater the retention rate of tensile strength and notched impact strength, the better the hydrolysis resistance.

[0060] The test results are shown in Table 3.

[0061] Table 3

[0062]

[0063]

[0064] From Example 1 and Comparative Example 1, it can be seen that in the preparation of glass fiber reinforced PBT material, the addition of hydrolysis resistant agent helps to improve the hydrolysis resistance of the material, and at the same time, the macromolecular structure of the hydrolysis resistant agent captures small molecules in the system during injection molding, reducing the generation of scale, and the macromolecular structure of the hydrolysis resistant agent is not easy to precipitate, unlike the existing conventional hydrolysis resistant agent which will further aggravate the scale.

[0065] From Examples 1-3, it can be seen that the content of small molecule substances in PBT resins with different intrinsic viscosities is different. From the examples, it can be seen that as the intrinsic viscosity of PBT resin in Examples 2, 1 and 3 increases, the scale mass gradually decreases, the tensile strength and notched impact strength retention rate slightly increases, and the hydrolysis resistance slightly increases. Therefore, considering comprehensively, the intrinsic viscosity of PBT resin can be selected as 0.6-1L / g, at which the glass fiber reinforced PBT material has lower scale mass and higher hydrolysis resistance during injection molding.

[0066] As can be seen from Examples 1, 4-5 and Comparative Example 3, with the increase of the content of glass fiber in the system of Examples 4, 5, 1 and Comparative Example 3, the hydrolysis resistance first increases and then decreases, and the content of glass fiber should not be too high, otherwise, due to the high content of glass fiber, the shear is large, the compatibility between the glass fiber and the matrix is poor, and thus the content of the small molecule material in the mold is increased and the hydrolysis resistance is poor. In the system of the present application, the mass percentage of glass fiber in the glass fiber reinforced PBT material is 15-30%, which can keep a low mold dirt mass and a high hydrolysis resistance.

[0067] As can be seen from Examples 1 and 6-7, with the increase of the diameter of the glass fiber, the mold dirt mass and the hydrolysis resistance in the system of the present application are basically unchanged.

[0068] As can be seen from Examples 1, 11-13 and Comparative Example 2, with the increase of the content of the hydrolysis resistance agent in Examples 11, 1, 12, 13 and Comparative Example 2, the mold dirt mass first decreases and then increases, and the tensile strength and the notched impact strength retention rate are basically unchanged; when the content of the hydrolysis resistance agent is low, the free PBT small molecule material cannot be fully captured, resulting in low mold dirt and low tensile strength and notched impact strength retention rate, and when the content of the capture agent is too high, the hydrolysis resistance agent is excessive, and the excess hydrolysis resistance agent acts as a small molecule material to produce mold dirt, which increases the mold dirt mass, so that the mold dirt is increased. Therefore, in the system of the present application, when the mass percentage of the hydrolysis resistance agent in the glass fiber reinforced PBT material is 1-2.5%, a low mold dirt mass and a high hydrolysis resistance can be maintained.

[0069] As can be seen from Examples 1 and 8-10, under the same weight parts, each type of hydrolysis resistance agent containing amide group can keep a low mold dirt mass and a high hydrolysis resistance. At the same time, in Comparative Example 5, 3-phenyl-2-propenoic acid containing carboxylic acid group is used, compared with Comparative Example 1 without hydrolysis resistance agent, although the mold dirt mass is reduced to a certain extent in Comparative Example 5, the hydrolysis resistance of the material cannot be significantly improved. Therefore, in the present application, only the hydrolysis resistance agent containing amide group can realize a low mold dirt mass and a high hydrolysis resistance at the same time.

[0070] As can be seen from Examples 1 and 14-15, due to the different contents of the auxiliary and PBT, the content of the small molecule produced by degradation in the processing process is different, when the content of the auxiliary is high, the auxiliary itself acts as a small molecule material, which can cause the mold dirt to be high, therefore, within the weight parts required in the present application, the components of the glass fiber reinforced PBT material can keep a low mold dirt mass and a high hydrolysis resistance in the injection molding process.

[0071] Finally, it should be noted that the above examples are merely intended to illustrate the technical solutions of the present application and not to limit the protection scope of the present application. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present application.

Claims

1. Use of a compound of the general formula (I) as a hydrolysis resistance agent in glass fibre reinforced PBT materials, characterised in that, The compound of the general formula (I) is shown as follows: X1, X2, X3, X4, X5 are each selected from any one of hydrogen atom, alkyl, alkoxy, halogen.

2. Use according to claim 1, wherein The compound of the general formula (I) includes at least one of phenylpropenamide, p-methyl cinnamic amide, trans-2,5-dimethoxycinnamic amide, 4-chlorocinnamic amide.

3. A glass fiber reinforced PBT material, characterized in that, The raw material components include the following weight parts: PBT resin 59-91 parts, glass fiber 14-32 parts, the hydrolysis-resistant agent of claim 1 or 2 0.7-2.6 parts, and auxiliary agent 0.1-2 parts.

4. The glass fiber reinforced PBT material according to claim 3, wherein, The method includes at least one of the following: A. The intrinsic viscosity of the PBT resin is 0.6-1 dL / g; B. The diameter of the glass fiber is 10-13 μm.

5. The glass fiber reinforced PBT material of claim 3, wherein, The mass percentage of the hydrolysis-resistant agent in the glass fiber reinforced PBT material is 1-2.5%.

6. The glass fiber reinforced PBT material of claim 3, wherein, The mass percentage of the glass fiber in the glass fiber reinforced PBT material is 15-30%.

7. The glass fiber reinforced PBT material of claim 3, wherein, The auxiliary agent includes an antioxidant and a lubricant.

8. A process for the production of a glass-fiber reinforced PBT material according to any one of claims 3 to 7, characterized in that The method includes the following steps: Mixing the PBT resin, the hydrolysis-resistant agent, the auxiliary agent and the glass fiber, melting under light, and then extruding and granulating to obtain the glass fiber reinforced PBT material.

9. The method for preparing glass fiber reinforced PBT material as described in claim 8, characterized in that, The wavelength of the light is 250-320 nm.

10. Use of the glass fiber reinforced PBT material of any one of claims 3-7 in the preparation of electronic appliances.

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