Low-ball-indentation-diameter low-float-glass-fiber-reinforced polyester material and preparation and use thereof

Abstract

The application relates to the technical field of polyester materials, and provides a low-ball-indentation-diameter low-fiber-floating glass fiber reinforced polyester material and preparation and application thereof. The glass fiber reinforced polyester material comprises PET, glass fiber, a nucleating agent, a crystallization promoter, a functional additive and a dispersant; the nucleating agent is a layered silicate surface modified by a titanate coupling agent; the crystallization promoter is a grafting product containing a high-temperature chain segment and a low-temperature chain segment; and the mass ratio of the crystallization promoter to the nucleating agent is 1-3:3-5. The layered silicate surface modified by the titanate coupling agent is used as the nucleating agent, and the crystallization promoter with a specific structure is also used. The synergistic effect of the components is utilized, and the use amount of the nucleating agent is controlled, so that the material has excellent heat resistance, a low ball indentation diameter, and the surface fiber floating is obviously reduced, and the material is suitable for air fryer cavities and bottom plate supports and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of polyester materials, and particularly relates to a low-ball-indentation-diameter low-float-glass-fiber-reinforced polyester material and preparation and application thereof. BACKGROUND

[0002] Polyethylene terephthalate (PET) is one of the most widely used engineering plastics on the market, which has excellent physical and mechanical properties in a wide temperature range, excellent electrical insulation, even at high temperature and high frequency, its electrical properties are still good, and it has good creep resistance, fatigue resistance, friction resistance and dimensional stability. However, PET material has the defects of slow crystallization rate, difficult molding processing, high molding temperature, long production cycle and poor impact performance.

[0003] In order to improve the performance of PET material, more and more researches on glass fiber reinforced PET material have been carried out, but in the composite system of glass fiber reinforced PET material, the addition of nucleating agent to improve the crystallization rate of glass fiber reinforced PET material is still the research focus, for example, patent application CN104559076A discloses a PET nucleating master batch and a preparation method thereof, using nano nucleating agent as PET nucleating agent to improve the crystallization rate; and for example, patent application CN110452502A discloses a low-warp high-heat-resistance polyester composite material and a preparation method thereof, using LCP, modified montmorillonite, silicon dioxide and sodium polyacrylate as a composite nucleating agent to improve the crystallization rate of glass fiber reinforced PET, the preparation method of the nucleating agent is relatively complex, and due to the presence of LCP, the cost of the nucleating agent is very high.

[0004] With the deepening of research, it is gradually found that only by adding nucleating agent to improve the crystallization rate of glass fiber reinforced PET material cannot improve the comprehensive performance of glass fiber reinforced PET material, especially when the glass fiber reinforced PET material is applied to electrical and electronic products, the hot ball indentation diameter is often the focus of application research, and controlling it at a lower value can bring better application effect, and there is currently no research report on the hot ball indentation diameter of glass fiber reinforced PET material.

[0005] In view of this, the present application is proposed. SUMMARY

[0006] It is generally believed that the hot ball indentation diameter is an important indicator for characterizing the heat resistance of non-metallic materials, which is usually tested by referring to the standard GB / T5169.21-2006 for non-metallic materials, but it is found in the research that for glass fiber reinforced PET materials, the size of the hot ball indentation diameter is not completely related to the crystallization rate and temperature resistance, for example: the hot deformation temperature of 30% GF reinforced PET material can reach 190 DEG C or more, which is not related to the specific formula, and due to the presence of glass fiber (and other nucleating agents) the crystallization rate is also improved to a certain extent, and we found in the actual test that the ball indentation diameter between different formulas is significantly different. That is, by improving the crystallization rate and temperature resistance of the glass fiber reinforced PET material, it cannot be ensured that the glass fiber reinforced PET material also has a low hot ball indentation diameter.

[0007] The present application provides a kind of low ball indentation diameter low float fiber glass reinforced polyester material and preparation and application thereof, to solve the defects that the hot ball indentation diameter of the above glass fiber reinforced PET material is not easy to control in lower value, by reasonably designing each component of glass fiber reinforced PET material, material has lower hot ball indentation diameter at the same time, other application performance also meets application demand, even has some improvement, especially its surface float fiber can be significantly reduced, hydrolysis retention rate etc., have very important significance.

[0008] Specifically, the present application provides a kind of glass fiber reinforced polyester material, comprising: PET, glass fiber, nucleating agent, crystallization promoter, functional additive and dispersant.

[0009] The nucleating agent is a surface modified layered silicate of coupling agent, the crystallization promoter is a grafting containing high temperature segment and low temperature segment, and the mass ratio of the crystallization promoter to the nucleating agent is 1-3:3-5.

[0010] The application uses a coupling agent to surface modify a layered silicate as a nucleating agent, and also uses a grafting product containing a high-temperature chain segment and a low-temperature chain segment as a crystallization promoter, utilizes the synergistic effect of the components and controls the use amount of the nucleating agent, so that the material has excellent heat resistance and a lower hot ball indentation diameter, and the synergistic effect specifically includes: the coupling agent in the nucleating agent can increase the surface contact area of the nucleating agent, so that the nucleating agent can be fully dispersed in the above-mentioned blended resin, and the layered silicate belongs to an inorganic nucleating agent, which is less likely to cause decomposition of the polyester compared with a conventional organic nucleating agent (such as Clariant's NAV101 or Honeywell 285P), thereby ensuring the mechanical properties and hot ball indentation properties of the material to a certain extent, and the crystallization promoter is a grafting product containing a high-temperature chain segment and a low-temperature chain segment, the low-temperature chain segment can well play a role in relaxing the molecular chain when the material is heated and melted, and then the high-temperature chain segment can improve the heat resistance of the material while playing a high-temperature nucleating agent role in the cooling stage, which, in cooperation with the nucleating effect of the layered silicate inorganic nucleating agent, allows the glass fiber reinforced PET material to be fully crystallized at a higher temperature, and more importantly, the grafting of the high-temperature chain segment and the low-temperature chain segment plays a key role, compared with the addition of a mixture of high-temperature chain segments and low-temperature chain segments alone, the graft copolymer molecular chain is uniform, and is more uniformly dispersed in the resin, which can better play the roles of relaxing the molecular chain and nucleation, so that the material has excellent heat resistance and a lower hot ball indentation property. When the mass ratio of the crystallization promoter to the nucleating agent is 1-3:3-5, the hot ball indentation property of the prepared glass fiber reinforced polyester material is lower, and in particular, if the content of the grafting product is too high, such as more than 7%, the heat distortion temperature of the material will be reduced, and it is found through experiments that an excessive amount of grafting product will not bring better hot ball indentation effect.

[0011] According to the glass fiber reinforced polyester material provided by the application, the grafting product takes PBT, PTT or PET as the main chain as the high-temperature chain segment, and takes PEG as the branch chain as the low-temperature chain segment; for example, the grafting product is one or more of PBT-PEG, PTT-PEG and PET-PEG. It is found through experiments that when the mass percentage of the PEG chain segment in the crystallization promoter is higher, the relaxing molecular chain effect of the low-temperature chain segment is more significant, and the material has better heat resistance and a lower hot ball indentation property, and preferably the mass percentage of the PEG chain segment in the crystallization promoter is 30% or more.

[0012] More preferably, the crystallization promoter is PBT-PEG and PTT-PEG. It is found through experiments that the crystallization promoter taking PBT and PTT as the high-temperature chain segment helps the crystallization nucleation at a higher temperature.

[0013] The mass percentage of the nucleating agent in the glass fiber reinforced polyester material is < 5%, and is preferably 3-5%. If the amount of the nucleating agent is too high (> 5%), the tensile strength of the material will be negatively affected, and the warpage performance and hot ball compression performance will be reduced to different degrees.

[0014] When the mass percentage of the nucleating agent in the glass fiber reinforced polyester material is in the above range, the mass ratio of the crystallization promoter to the nucleating agent helps to fully exert the synergistic effect of the nucleating agent and the crystallization promoter, and improve the comprehensive performance of the glass fiber reinforced polyester material.

[0015] The glass fiber reinforced polyester material provided by the application further comprises PBT, and the mass ratio of the PET to the PBT is 50-60:5-15.

[0016] The application uses PBT and PET in combination. PBT has a high crystallization rate, and adding it to PET can improve the crystallization rate of PET. However, when the amount of PBT is high, the glass fiber reinforced material is prone to warpage deformation. It is found in experiments that, by using the formulation of the application and reasonably designing the proportion of each component, the glass fiber reinforced polyester material containing PBT has excellent heat resistance and a low hot ball compression indentation diameter, and the surface fiber floating and warpage deformation of the obtained product can be well controlled. Further preferably, the mass ratio of the PET to the PBT is 50-60:5-10.

[0017] The glass fiber reinforced polyester material provided by the application is characterized in that the nucleating agent is a titanate coupling agent surface modified layered silicate; and / or the content of the titanate coupling agent in the nucleating agent is 0.1-0.3% of the mass of the layered silicate.

[0018] In order to fully exert the synergistic effect of the nucleating agent and the crystallization promoter and effectively control the surface fiber floating of the glass fiber reinforced polyester material, it is preferred that the coupling agent in the nucleating agent is a titanate coupling agent, and the content of the titanate coupling agent is controlled in the above range.

[0019] The glass fiber reinforced polyester material provided by the application is characterized in that the dispersing agent is an oxidized polyethylene wax with an acid value of 25-30 mgKOH / g.

[0020] The application uses high-acid-value oxidized polyethylene wax as a dispersant, which on the one hand plays a good dispersion role, allowing glass fibers and nucleating agents to be fully dispersed in resin, so that the material has relatively uniform hot ball pressure performance; meanwhile, it is accidentally found in the experimental verification process that high-acid-value polyethylene wax can improve the bonding force of glass fibers and resin, plays an "anchoring" role, thereby effectively reducing the surface fiber floating of the glass fiber reinforced PET material, and has the best appearance performance within the range of 0.5-1% addition amount, and when the addition amount is small, the effect is not strong, and the appearance is not obviously improved; and when the addition amount exceeds the range, the effect will not continue to improve, therefore, the mass percentage of the dispersant in the glass fiber reinforced polyester material is preferably 0.5-1%.

[0021] According to the glass fiber reinforced polyester material provided by the application, the functional additive comprises one or more of a toughening agent, an antioxidant and a hydrolysis-resistant agent.

[0022] According to the glass fiber reinforced polyester material provided by the application, the toughening agent is ethylene-methyl acrylate-glycidyl methacrylate.

[0023] The hydrolysis-resistant agent is polycarbodiimide, and the molecular weight is 3000-9000 g / mol.

[0024] The glass fiber reinforced polyester material further comprises an antioxidant, and the antioxidant is 1010 and 168.

[0025] In order to obtain a glass fiber reinforced polyester material with better performance, preferably, the PET is homopolymer fiber-grade PET, and the viscosity is 0.65-0.68 dl / g; and / or, the viscosity of the PBT is 0.98-1.02 dl / g.

[0026] According to the glass fiber reinforced polyester material provided by the application, the glass fiber reinforced polyester material comprises, by weight fraction, PET 50-60 parts, PBT 5-15 parts, glass fibers 20-30 parts, a nucleating agent 3-5 parts, a crystallization promoter 1-3 parts, a toughening agent 1-3 parts, a dispersant 0.5-1 part, an antioxidant 0.3-0.5 part and a hydrolysis-resistant agent 0.5-1 part. It is found in the test that the above-mentioned formulation can be used to obtain a glass fiber reinforced polyester material with better performance.

[0027] The application further provides a preparation method of the glass fiber reinforced polyester material as described above, comprising the following steps:

[0028] The dried PET, titanate coupling agent surface modified layered silicate, crystallization promoter, functional additive and dispersant are mixed to obtain a mixture;

[0029] The mixture is subjected to melt extrusion while the glass fibers are added, and the glass fiber reinforced polyester material is obtained.

[0030] The preparation method of the glass fiber reinforced polyester material in the application specifically comprises the following steps:

[0031] (1) The titanate coupling agent and the layered silicate are weighed according to the proportion, and then stirred by using a high-speed stirrer, the stirring speed is 300-500 rpm, and the stirring time is 1-3 min, to obtain the titanate coupling agent surface modified layered silicate, i.e. the nucleating agent.

[0032] (2) The PET resin is dried at 120-160 ℃ for more than 4 h, and when the particles change from transparent to milky white, the glass fiber, the nucleating agent, the crystallization promoter, the functional additive and the dispersant are weighed according to the weight ratio, and then mixed uniformly by using a mixing pot to obtain a mixture; when the remaining components such as PBT are added, they are added into the resin together with the glass fiber and the like for mixing.

[0033] (3) The above mixture is added into a double-screw extruder for melt extrusion, and the glass fiber is added at the same time, and after water cooling, air cooling and granulation, the glass fiber reinforced polyester material is prepared. The glass fiber used in the application can be one of chopped glass fiber, continuous fiber and flat glass fiber; the chopped glass fiber and the flat glass fiber are fed by the side feeding mode, and the continuous fiber is fed from the exhaust port.

[0034] The application also provides the application of the glass fiber reinforced polyester material as described above. The glass fiber reinforced polyester material prepared by the application has a lower hot ball indentation diameter and a lower floating fiber, the crystallization rate is obviously improved compared with the conventional glass fiber reinforced PET material, can meet the demolding requirements in actual production, the material has a ball indentation diameter of less than 1.6 mm at 200 ℃, the tensile strength retention rate is more than 90% after a double 85 test for 2000 h, has excellent heat resistance and hydrolysis resistance, and is widely applied to air fryer cavities, bottom plate supports and other temperature-resistant and hydrolysis-resistant cooking electrical appliance parts.

[0035] The application provides a glass fiber reinforced polyester material with low ball indentation diameter and low floating fiber, and preparation and application thereof. The layered silicate surface modified by a coupling agent is used as a nucleating agent, and a crystallization promoter with a specific structure is also used, the synergistic effect of the components is utilized, and the use amount of the nucleating agent is controlled, so that the material has excellent heat resistance and a low hot ball indentation diameter.

[0036] In addition, the surface floating fiber and the hydrolysis retention rate of the glass fiber reinforced polyester material are also significantly improved.

[0037] The ball indentation diameter of the glass fiber reinforced polyester material is 1.35-1.58 mm, the tensile strength is 105-118 MPa, the hydrolysis retention rate is 90-91.5%, the warpage is 0.3-1.6, the appearance is good, and the surface fiber is less. By further optimizing the raw materials, a composite material with a ball indentation diameter of 1.48-1.58 mm, a tensile strength of 116-118 MPa, a hydrolysis retention rate of 90.8-91.3%, a warpage of 0.3-0.6, a good appearance, and less surface fiber can be prepared. DETAILED DESCRIPTION

[0038] To make the purpose, technical scheme and advantages of the present application clearer, the technical scheme in the present application will be described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0039] In the embodiments, the specific technology or conditions not specified are carried out according to the technology or conditions described in the literature in the art or according to the product instructions. The reagents or instruments not specified by the manufacturer are conventional products that can be purchased through regular channels.

[0040] In the embodiments of the present application, the relevant material information is as follows: PBT-PEG, PTT-PEG and PET-PEG represent polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT) and polyethylene terephthalate (PET) grafted polyvinyl alcohol (PEG) copolymer, respectively. In the copolymer, the number average molecular weight of the PEG raw material used for preparation is less than or equal to 1000 g / mol, and the PEG segment accounts for more than 30% of the mass percentage of the grafted copolymer.

[0041] Table 1

[0042]

[0043]

[0044] Examples 1-5

[0045] A preparation method of a glass fiber reinforced polyester material, specifically comprising the following steps:

[0046] (1) First, the titanate coupling agent and the layered silicate are weighed according to the proportion, and then stirred using a high-speed stirrer at a stirring speed of 400 rpm for 1 min to obtain a nucleating agent. The content of the titanate coupling agent is 0.2% of the mass of the layered silicate.

[0047] (2) The PET is dried at 140℃ for 4h or more, and when the granules change from transparent to milky white, the mixture kettle is used to mix the PBT, glass fiber, nucleating agent, crystallization promoter, toughening agent and dispersant according to the weight ratio, to obtain a mixture; wherein the dispersant is an oxidized polyethylene wax with an acid value of 30mgKOH / g (dispersant 1), and when the remaining components such as antioxidants and hydrolysis-resistant agents are added, they need to be added into the resin together with the nucleating agent and crystallization promoter for mixing.

[0048] (3) The above mixture is added to a twin-screw extruder for melt extrusion, and glass fiber is added at the same time, and after water cooling, air cooling and granulation, a glass fiber reinforced polyester material is prepared. Among them, the chopped glass fiber and flat glass fiber are fed by side feeding, and the continuous fiber is fed from the exhaust port.

[0049] The formula table of the above examples 1-5 (by weight fraction) is as follows:

[0050] Table 2

[0051]

[0052]

[0053] Example 6

[0054] A method for preparing a glass fiber reinforced polyester material, the steps of which are basically the same as those of example 1, except that the dispersant is replaced by an oxidized polyethylene wax with an acid value of 15mgKOH / g.

[0055] Example 7

[0056] A method for preparing a glass fiber reinforced polyester material, the steps of which are basically the same as those of example 1, except that the titanium ester coupling agent in the nucleating agent is replaced by silane coupling agent KH-560.

[0057] Example 8

[0058] A method for preparing a glass fiber reinforced polyester material, the steps of which are basically the same as those of example 1, except that the fraction of PET is adjusted to 40 parts, and the fraction of PBT is adjusted to 20 parts.

[0059] Comparative examples 1-2

[0060] A method for preparing a glass fiber reinforced polyester material, the steps of which are basically the same as those of example 1, except that the formula is replaced by the formula in the following table:

[0061] Table 3

[0062]

[0063]

[0064] Comparative Example 3

[0065] A method for preparing a glass fiber reinforced polyester material, the steps of which are substantially the same as those of Example 1, except that the mass percentage of nucleating agent in the glass fiber reinforced polyester material is increased to 6%.

[0066] Comparative Example 4

[0067] A method for preparing a glass fiber reinforced polyester material, the steps of which are substantially the same as those of Example 3, except that the crystallization promoter is replaced by an equal mass of a blend of PET (number average molecular weight 25,000 g / mol) and PEG (number average molecular weight 1,000 g / mol) at a mass ratio of 1:1.

[0068] Comparative Example 5

[0069] A method for preparing a glass fiber reinforced polyester material, the steps of which are substantially the same as those of Example 1, except that the crystallization promoter is replaced by an equal mass of a blend of PBT (number average molecular weight 35,000 g / mol) and PEG (number average molecular weight 1,000 g / mol) at a mass ratio of 1:1.

[0070] The glass fiber reinforced polyester materials prepared in Examples 1-9 and Comparative Examples 1-5 were tested, and the testing methods were as follows:

[0071] The materials were first dried at 120°C for 4 h, and then standard test bars were prepared using an injection molding machine, and then tested in accordance with the following standards (the average value of 5 groups of data was taken for each item):

[0072] The tensile strength test standard referred to GB / T1040.1-2018;

[0073] The hydrolysis retention rate was the ratio of the tensile strength after 2000 h of testing in a double 85 high temperature and high humidity test chamber (test conditions: 85°C and relative humidity 85 RH%) to the tensile strength before the test;

[0074] The hot ball pressure test referred to the standard GB / T5169.21-2006, and the test temperature was 200°C;

[0075] The surface fiber floating condition was evaluated from visual observation and surface feel, and was divided into three levels: good, medium, and poor;

[0076] The warpage was tested by injection molding a round piece, with a diameter of 100 mm and a thickness of 2 mm, and after natural cooling, one side was pressed and the gap on the other side was tested.

[0077] The test results were as follows:

[0078] Table 4

[0079]

[0080] Table 5

[0081]

[0082] As can be seen from Example 1 and Example 7, the sample prepared using the nucleating agent treated with silane coupling agent has poor appearance, mainly manifested in that there are many floating fibers on the surface, which indicates that the silane coupling agent is not suitable for treating inorganic substances in powder state, and the sample prepared using the nucleating agent treated with titanate coupling agent has good appearance and ball indentation diameter performance.

[0083] As can be seen from Example 1 and Example 8, when the content of PBT is high, although the ball indentation diameter can be reduced, the warpage of the material will be significantly increased.

[0084] As can be seen from Example 1 and Comparative Examples 1-2, the combination of the nucleating agent and the crystallization promoter of the present application has lower ball indentation diameter than the conventional nucleating agent plus crystallization promoter scheme.

[0085] As can be seen from Example 1 and Comparative Example 3, when the amount of the nucleating agent exceeds 5 parts, the tensile strength of the material decreases obviously, and when the scheme of the present application is adopted, the amount of the nucleating agent needs to be strictly controlled to fully utilize the strength advantage brought by the glass fiber.

[0086] As can be seen from Example 1, Example 3, Comparative Example 4 and Comparative Example 5, compared with introducing the PEG as a low-temperature segment into the copolymer in a blending manner, introducing the PEG as a low-temperature segment into the copolymer in a branched structure can more effectively reduce the ball indentation diameter of the material and has higher hydrolysis retention rate.

[0087] The glass fiber reinforced polyester material prepared by the method for preparing a glass fiber reinforced polyester material in the present application has lower hot ball indentation diameter and lower floating fiber, and the crystallization rate is obviously higher than that of the conventional glass fiber reinforced polyester material, which can meet the demolding requirements in actual production, the material has a ball indentation diameter of less than 1.6 mm at 200℃, the tensile strength retention rate is more than 90% after double 85 test for 2000h, has excellent heat resistance and hydrolysis resistance, and is widely used in air fryer cavities and bottom plate supports and other temperature-resistant and hydrolysis-resistant cooking appliances.

[0088] It should be pointed out finally that the above embodiments are only used to illustrate the technical solutions of the present application, but not to limit the same; and although the present application has been described in detail with reference to the foregoing embodiments, it should be appreciated by those skilled in the art that the technical solutions recorded in the foregoing embodiments can be modified, or some technical features thereof can be replaced equivalently; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A glass fiber reinforced polyester material, characterized in that, By weight, it includes: 50-60 parts PET, 5-15 parts PBT, 20-30 parts glass fiber, 3-5 parts nucleating agent, 1-3 parts crystallization promoter, 1-3 parts toughening agent, 0.5-1 part dispersant, 0.3-0.5 parts antioxidant and 0.5-1 part hydrolysis resistant agent; The mass ratio of PET to PBT is 50~60:5~15; The nucleating agent is a surface-modified layered silicate of titanate coupling agent; the titanate coupling agent is NDZ-201; the mass percentage of the nucleating agent in the glass fiber reinforced polyester material is ≤5%; The crystallization accelerator is a graft containing high-temperature segments and low-temperature segments, and the mass ratio of the crystallization accelerator to the nucleating agent is 1~3:3~5; in the graft, PBT, PTT or PET is used as the main chain as the high-temperature segment, and PEG is used as the side chain as the low-temperature segment. The dispersant is oxidized polyethylene wax with an acid value of 25~30 mgKOH / g.

2. The glass fiber reinforced polyester material according to claim 1, characterized in that, The nucleating agent contains 0.1 to 0.3% of the mass of the layered silicate as a titanate coupling agent.

3. The method for preparing the glass fiber reinforced polyester material according to claim 1 or 2, characterized in that, include: The dried PET, PBT, nucleating agent, crystallization accelerator, toughening agent, antioxidant, hydrolysis resistant agent and dispersant are mixed to obtain a mixture; Glass fibers are added during the melt extrusion of the mixture to obtain the final product.

4. The application of the glass fiber reinforced polyester material as described in claim 1 or 2 in heat-resistant and hydrolysis-resistant cooking appliance components.

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