阅读说明：本技术 一种反应型成核添加剂及其制备方法和应用 (Reactive nucleating additive and preparation method and application thereof ) 是由 谢永光 杨建� 李晓宇 蒋波 刘晓梅 刘旭 于 2021-08-19 设计创作，主要内容包括：本发明涉及纤维增强复合材料领域,具体涉及一种反应型成核添加剂及其制备方法和应用。为了解决现有技术需要同时加入成核剂和结晶促进剂来缓解PET结晶慢的问题,本发明提出一种反应型成核添加剂及其制备方法和应用。反应型成核添加剂羟基聚乙二醇羧酸钠(OH-PEG-COONa)集PET成核剂和结晶促进剂功能于一身：分子链中含有的-COONa官能团起到了PET异相成核剂的作用,可以显著提高PET成核效率；含有的聚乙二醇链段作为结晶促进剂,可以通过减少PET大分子链之间的氢键密度和范德华力,降低PET大分子之间的相互作用,提高了运动能力,促进了PET大分子链折叠进入晶区的能力。(The invention relates to the field of fiber reinforced composite materials, in particular to a reactive nucleating additive and a preparation method and application thereof. In order to solve the problem that a nucleating agent and a crystallization promoter are required to be added simultaneously to relieve slow crystallization of PET in the prior art, the invention provides a reactive nucleating additive and a preparation method and application thereof. The reaction type nucleating additive sodium hydroxy polyethylene glycol carboxylate (OH-PEG-COONa) integrates the functions of a PET nucleating agent and a crystallization promoter into a whole: the-COONa functional group contained in the molecular chain plays a role of a PET heterogeneous nucleating agent, and the PET nucleating efficiency can be obviously improved; the polyethylene glycol chain segment contained is used as a crystallization promoter, and can reduce the interaction between PET macromolecules by reducing the hydrogen bond density and van der Waals force between the PET macromolecule chains, improve the movement capacity and promote the capacity of folding the PET macromolecule chains to enter a crystal region.)

1. A reactive nucleating additive characterized by the structure shown below:

wherein m ranges from 10 to 50 and the molecular weight is 500-2000 g/mol.

2. A process for preparing a reactive nucleating additive as claimed in claim 1, which comprises mixing carboxyl hydroxy polyethylene glycol with sodium hydroxide as raw materials.

3. The method of preparing a reactive nucleating additive according to claim 2, wherein the reaction temperature is 40-60 ℃;

preferably, the molar ratio of the carboxyl hydroxyl polyethylene glycol to the sodium hydroxide is 1: 0.9.

4. A polyester specialty material for continuous fiber reinforcement comprising polyethylene terephthalate and the reactive nucleating additive of claim 1.

5. The special material for the continuous fiber reinforced polyester as claimed in claim 4, wherein the special material for the continuous fiber reinforced polyester further comprises a flow modifier, a release agent and an antioxidant;

preferably, the polyethylene terephthalate is 99.2-91.0 parts by weight, the reactive nucleating additive is 0.5-5 parts by weight, the flow modifier is 0.1-2 parts by weight, the release agent is 0.1-1 part by weight, and the antioxidant is 0.1-1 part by weight.

6. The method for preparing the polyester special material for continuous fiber reinforcement according to claim 4 or 5, which is characterized by comprising the steps of mixing raw materials, extruding, cooling, drawing, drying and granulating;

preferably, the extrusion parameters are 260-300 ℃, the rotating speed of the main screw is 50-200 r/min, and the rotating speed of the feeding screw is 5-20 r/min.

7. A continuous fiber-reinforced PET composite material comprising the reactive nucleating additive according to claim 1 and/or the polyester specialty material for continuous fiber reinforcement according to claim 4 or 5.

8. The preparation method of the continuous fiber reinforced PET composite material of claim 7, wherein the continuous fiber reinforced PET composite material is obtained by extruding and melting the special polyester material for continuous fiber reinforcement to obtain a PET molten pool, preheating the continuous glass fiber, infiltrating resin into the PET molten pool, cooling, drawing, drying and granulating.

9. Use of the reactive nucleating additive according to claim 1 and/or the polyester specialty material for continuous fiber reinforcement according to claim 4 or 5 for the preparation of a continuous fiber PET composite.

10. A composite fiber material comprising the reactive nucleating additive according to claim 1 and/or the polyester specialty for continuous fiber reinforcement according to claim 4 or 5 and/or the PET composite for continuous fiber reinforcement according to claim 7.

Technical Field

The invention relates to the field of fiber reinforced composite materials, in particular to a reactive nucleating additive and a preparation method and application thereof.

Background

The information in this background section is only for enhancement of understanding of the general background of the invention and is not necessarily to be construed as an admission or any form of suggestion that this information forms the prior art that is already known to a person of ordinary skill in the art.

Polyethylene terephthalate (PET) is the most commonly used polyester raw material, has good strength and modulus as a high melting point crystalline polymer, excellent abrasion resistance, creep resistance, weather resistance and organic solvent resistance, and is widely used as fibers, packaging materials and engineering plastics.

PET is saturated polyester formed by esterification and polycondensation of terephthalic acid and ethylene glycol, a repeating unit contains rigid benzene rings, ester groups and flexible ethylene units, and because the chain segments of the ethylene units are too short, the benzene rings and the ester groups in the PET molecular chains form a conjugated system, when molecules move, the rotational energy is too large, methylene and the benzene rings can only move together as a whole, although the mechanical strength and the melting point of the PET are improved by the rigidity of the huge chain segments, the remarkable molecular movement energy resistance also prevents the regular arrangement in crystal nuclei. This results in a half-crystallization time of 62.5 seconds for PET, while nylon 6 and 66, which are also used as engineering plastics, have only 7.14 and 0.66 seconds for half-crystallization time, and PET has a cold crystallization peak at about 124 ℃, so PET with too low crystallization rate is difficult to directly extrude, and the problems of slow crystallization and difficult demolding during injection molding also exist, thus the injection molding efficiency is seriously affected.

The continuous fiber reinforced thermoplastic composite material has the advantages of high modulus, good strength and good creep resistance, but the currently widely used continuous fiber reinforced composite material mainly comprises polypropylene (PP) or nylon (PA), and PET with high strength, good weather resistance and low cost is rarely used as the thermoplastic resin for coating the continuous fibers, as long as the PET is low in crystallization rate and cold crystallization peak. Therefore, increasing the crystallization rate of PET, and reducing or eliminating the cold crystallization peak are key points in the preparation of continuous fiber reinforced hot PET composites.

In order to increase the crystallization rate of PET, most researchers have employed methods of adding a nucleating agent and a crystallization promoter. Nucleating agents include three broad classes: inorganic nucleating agent, organic nucleating agent and high molecular nucleating agent, the inorganic nucleating agent is commonly used talcum powder, silicon dioxide and the like, the organic nucleating agent is sodium carboxylate, potassium carboxylate and calcium salt, and the high molecular nucleating agent is polytetrafluoroethylene powder, ionomer and the like. The crystallization promoter is mainly a plasticizer containing ester and ether groups, and can improve the mobility of PET macromolecular chains.

In the prior art, the crystallization rate of PET is improved, and after montmorillonite and TA-401A are compounded to be used as a nucleating agent in some technologies, the crystallization half-time is 1/4 of pure PET, and the cold crystallization peak temperature is reduced by 5.71-11.85 ℃. Or 0.5-5% of sodium chloride and 0.5-10% of polyoxyethylene are added as nucleating agents and crystallization promoters, and the glass fiber reinforced PET can be molded at 70-100 ℃.

The inventor finds that, as can be seen from the existing research, in order to solve the problem of slow crystallization of PET, researchers add different types of nucleating agents and crystallization promoters, and the added nucleating agents have compatibility with PET, such as inorganic or organic nucleating agents, which cause poor dispersibility in the PET matrix, and may have a risk of precipitation with time, and the nucleating agents and the crystallization promoters need to be added at the same time to effectively increase the crystallization rate of PET.

Disclosure of Invention

In order to solve the problem that a nucleating agent and a crystallization promoter are required to be added simultaneously to relieve slow crystallization of PET in the prior art, the invention provides a reactive nucleating additive and a preparation method and application thereof. The reaction type nucleating additive sodium hydroxy polyethylene glycol carboxylate (OH-PEG-COONa) integrates the functions of a PET nucleating agent and a crystallization promoter into a whole: the-COONa functional group contained in the molecular chain plays a role of a PET heterogeneous nucleating agent, and the PET nucleating efficiency can be obviously improved; the polyethylene glycol chain segment contained is used as a crystallization promoter, and can reduce the interaction between PET macromolecules by reducing the hydrogen bond density and van der Waals force between the PET macromolecule chains, improve the movement capacity and promote the capacity of folding the PET macromolecule chains to enter a crystal region. In addition, a hydroxyl functional group contained in the OH-PEG-COONa molecule can form covalent bond connection with COOH at the end of the PET chain through esterification reaction, and the OH-PEG-COONa is grafted to a PET macromolecular chain to form a PET-hydroxypolyethyleneglycol sodium carboxylate graft, so that the PET-hydroxypolyethyleneglycol sodium carboxylate graft is not easy to separate out on the surface of PET. After the reactive sodium hydroxy polyethylene glycol carboxylate additive is added into PET, the semi-crystallization period of the PET is obviously reduced to 8.41 seconds from 62.5 seconds of pure PET, and the cold crystallization peak temperature is reduced to 98.02 ℃.

Specifically, the invention is realized by the following technical scheme:

in a first aspect of the present invention, there is provided a reactive nucleating additive having the structure shown below:

wherein m ranges from 10 to 50 and the molecular weight is 500-2000 g/mol.

The second aspect of the invention provides a preparation method of a reactive nucleating additive, which comprises the steps of mixing carboxyl hydroxyl polyethylene glycol and sodium hydroxide as raw materials for reaction.

In a third aspect of the invention, a polyester special material for continuous fiber reinforcement is provided, which comprises polyethylene terephthalate and a reactive nucleating additive.

The invention provides a preparation method of the polyester special material for continuous fiber reinforcement, which comprises the steps of mixing raw materials, extruding, cooling, drawing, drying and granulating.

In a fifth aspect of the invention, a continuous fiber reinforced PET composite material is provided, which comprises a reaction type nucleation additive and/or a polyester special material for continuous fiber reinforcement.

The invention provides a preparation method of the continuous fiber reinforced PET composite material, which comprises the steps of extruding and melting the special polyester material for continuous fiber reinforcement to obtain a PET molten pool, preheating continuous glass fibers, infiltrating resin into the PET molten pool, cooling, drawing, drying and granulating to obtain the continuous fiber reinforced PET composite material.

The seventh aspect of the invention provides an application of a reaction type nucleating additive and/or a polyester special material for continuous fiber reinforcement in the preparation of a continuous fiber PET composite material.

In the eighth aspect of the invention, the composite fiber material comprises a reactive nucleating additive and/or a polyester special material for continuous fiber reinforcement and/or a continuous fiber reinforced PET composite material.

One or more of the technical schemes have the following beneficial effects:

1) the-COONa functional group contained in the molecular chain of the hydroxyl polyethylene glycol sodium carboxylate (OH-PEG-COONa) plays the role of a PET heterogeneous nucleating agent, and the PET nucleating efficiency can be obviously improved; the polyethylene glycol chain segment contained is used as a crystallization promoter, and can reduce the interaction between PET macromolecules by reducing the hydrogen bond density and van der Waals force between the PET macromolecule chains, improve the movement capacity and promote the capacity of folding the PET macromolecule chains to enter a crystal region.

2) Hydroxyl functional groups contained in OH-PEG-COONa molecules can form covalent bond connection with COOH at the end of a PET chain through esterification reaction, and OH-PEG-COONa is grafted to a PET macromolecular chain to form a PET-hydroxyl polyethylene glycol sodium carboxylate graft, so that the PET-hydroxyl polyethylene glycol sodium carboxylate graft is not easy to separate out on the surface of PET.

3) From the aspect of improving the crystallization performance of PET, after the reactive sodium hydroxy polyethylene glycol carboxylate additive is added into the PET, the semi-crystallization period of the PET is obviously reduced to 8.41 seconds from 62.5 seconds of pure PET, and the cold crystallization peak temperature is reduced to 98.02 ℃.

4) From the aspect of the performance of the glass fiber product, the PET, OH-PEG-COONa, the flow modifier, the release agent and the antioxidant are melted and mixed to prepare the PET composite material with high crystallization rate and high fluidity, which is very suitable for being used as a polyester material special for continuous fiber reinforcement, and the continuous fiber reinforced PET composite material with the glass fiber content of 50 percent can be prepared, and the yield reaches 800kg per hour. In addition, the continuous fiber reinforced PET composite has excellent tensile strength and unnotched impact strength.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the invention and together with the description serve to explain the invention and not to limit the invention. Embodiments of the invention are described in detail below with reference to the attached drawing figures, wherein:

FIG. 1 is a flow chart of the preparation of a continuous fiber-reinforced PET composite material according to example 1 of the present invention;

FIG. 2 is a DSC curve of a polyester specialty material for continuous fiber reinforcement prepared according to various embodiments of the present invention;

wherein: 1. the device comprises a material supplementing bin, 2 a weightless scale, 3 a double-screw extruder, 4 a glass fiber raw material rack, 5a preheating oven, 6 a molten pool die head, 7 a cooling water tank, 8 a blow-drying machine, 9 a traction machine, 10 a grain cutting machine, 11 and a vibrating screen.

Detailed Description

The invention will be further illustrated with reference to the following specific examples. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. The experimental procedures, in which specific conditions are not noted in the following examples, are generally carried out according to conventional conditions or according to conditions recommended by the manufacturers.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present disclosure. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.

The continuous fiber reinforced thermoplastic composite material has the advantages of high modulus, good strength and good creep resistance, but the currently widely used continuous fiber reinforced composite material mainly comprises polypropylene (PP) or nylon (PA), and PET with high strength, good weather resistance and low cost is rarely used as the thermoplastic resin for coating the continuous fibers, as long as the PET is low in crystallization rate and cold crystallization peak. Therefore, increasing the crystallization rate of PET, and reducing or eliminating the cold crystallization peak are key points in the preparation of continuous fiber reinforced hot PET composites.

In some technologies, a compounded high-molecular nucleating agent FH2 is adopted, and after the compounded high-molecular nucleating agent FH2 is melt-blended with PET, the semi-crystallization period of the PET is shortened by 5 times, and the nucleating agent is considered to play a good heterogeneous nucleation role. In other technologies, organic modified montmorillonite is used as a PET nucleating agent, the semicrystallization period is shortened by half, the cold crystallization peak temperature is reduced by 0.33-4.92 ℃, when montmorillonite and TA-401A are compounded to be used as the nucleating agent, the semicrystallization period is 1/4 of pure PET, and the cold crystallization peak temperature is reduced by 5.71-11.85 ℃. In addition, some researchers disclose a preparation method of the chemical nucleation glass fiber reinforced polyester composite material, and 0.5-5% of sodium chloride and 0.5-10% of polyethylene oxide are added to be used as a nucleating agent and a crystallization promoter, so that the glass fiber reinforced PET can be molded at 70-100 ℃.

However, these methods are all added with different types of nucleating agents and crystallization promoters, and the added nucleating agents have compatibility problems with PET, such as inorganic or organic nucleating agents, which cause poor dispersibility in PET matrix, and may have a risk of precipitation with time, and the nucleating agents and crystallization promoters need to be added to effectively increase the crystallization rate of PET.

Therefore, the invention provides a reactive nucleating additive, and a preparation method and application thereof. Specifically, the invention is realized by the following technical scheme:

in a first aspect of the present invention, there is provided a reactive nucleating additive having the structure shown below:

wherein m ranges from 10 to 50 and the molecular weight is 500-2000 g/mol.

The reaction type nucleating additive sodium hydroxy polyethylene glycol carboxylate (OH-PEG-COONa) integrates the functions of a PET nucleating agent and a crystallization promoter into a whole: the-COONa functional group contained in the molecular chain plays a role of a PET heterogeneous nucleating agent, and the PET nucleating efficiency can be obviously improved; the polyethylene glycol chain segment contained is used as a crystallization promoter, and can reduce the interaction between PET macromolecules by reducing the hydrogen bond density and van der Waals force between the PET macromolecule chains, improve the movement capacity and promote the capacity of folding the PET macromolecule chains to enter a crystal region. In addition, a hydroxyl functional group contained in the OH-PEG-COONa molecule can form covalent bond connection with COOH at the end of the PET chain through esterification reaction, and the OH-PEG-COONa is grafted to a PET macromolecular chain to form a PET-hydroxypolyethyleneglycol sodium carboxylate graft, so that the PET-hydroxypolyethyleneglycol sodium carboxylate graft is not easy to separate out on the surface of PET. After the reactive sodium hydroxy polyethylene glycol carboxylate additive is added into PET, the semi-crystallization period of the PET is obviously reduced to 8.41 seconds from 62.5 seconds of pure PET, and the cold crystallization peak temperature is reduced to 98.02 ℃.

The second aspect of the invention provides a preparation method of a reactive nucleating additive, which comprises the steps of mixing carboxyl hydroxyl polyethylene glycol and sodium hydroxide as raw materials for reaction.

The synthesis process of the reaction type nucleation additive sodium hydroxy polyethylene glycol carboxylate is as follows:

the n range in the carboxyl hydroxyl polyethylene glycol is 10-50, and the molecular weight is 500-2000 g/mol, experiments show that along with the increase of the molecular weight of the carboxyl hydroxyl polyethylene glycol, the lower the temperature of a cold crystallization peak in a DSC curve of the special polyester material for continuous fiber reinforcement, the higher the relative crystallinity, because the larger the temperature difference is, the higher the nucleation driving force of the polyester is, but when the molecular weight is too high, the capability of the polyethylene glycol chain segment for promoting the movement of the polyester macromolecular chain is reduced, and the crystallization speed of the polyester is reduced on the contrary.

Too low a reaction temperature results in a low reaction rate and too high a reaction temperature results in degradation side reactions, and thus in one or more embodiments of the invention, the reaction temperature is in the range of 40 to 60 ℃, preferably 50 ℃.

Preferably, the molar ratio of the carboxyl hydroxyl polyethylene glycol to the sodium hydroxide is 1:0.9, so that the sodium hydroxide can be completely reacted by carboxyl groups, and no residue can be generated, and more than 1:0.9 can be generated, and the residue can possibly cause the degradation of the polyester in the processing process.

In a third aspect of the invention, a polyester special material for continuous fiber reinforcement is provided, which comprises polyethylene terephthalate and a reactive nucleating additive.

In one or more embodiments of the present invention, the continuous fiber reinforced polyester specialty media further comprises a flow modifier, a release agent, and an antioxidant;

the flow modifier is selected from one or more of HyPer C181, zinc stearate and calcium stearate;

the release agent is selected from one or more of AClyn 285A, silicone and tetrafluoroethylene;

the antioxidant is selected from one or more of 1098, 1010 and 168;

the PET composite material with high crystallization rate and high fluidity prepared by melting and mixing the PET, the OH-PEG-COONa, the flow modifier, the release agent and the antioxidant is very suitable for being used as a special polyester material for continuous fiber reinforcement, and the continuous fiber reinforced PET composite material with the glass fiber content of 50 percent can be prepared, and the yield reaches 800kg per hour.

The grafting reaction of the sodium hydroxy polyethylene glycol carboxylate and PET (intrinsic viscosity is 0.90-1.10dL/g, n is between 150 and 220) is as follows:

the m range in carboxyl hydroxyl polyethylene glycol is 10-50, and the molecular weight is 500-2000 g/mol.

Preferably, the weight portions of the polyethylene glycol terephthalate are 99.2-91.0 portions, 0.5-5 portions of sodium hydroxy polyethylene glycol carboxylate (reaction type nucleation additive), 0.1-2 portions of flow modifier, 0.1-1 portion of release agent and 0.1-1 portion of antioxidant.

In some embodiments of the invention, the principle that the synthesized sodium hydroxypolyethylene glycol carboxylate nucleating additive promotes the crystallization rate of PET is as follows: when the nucleating additive and PET are subjected to melt blending, the terminal hydroxyl of the nucleating additive and the terminal carboxyl of the PET are subjected to esterification reaction, the nucleating additive is grafted to the PET through a covalent bond, a-COONa functional group contained in the nucleating additive becomes a seed crystal of PET heterogeneous nucleation, a PET macromolecular chain segment is gathered to-COONa in a molten state, the interaction of hydrogen bonds and van der Waals force between PET macromolecular chains is weakened due to the existence of a long-chain polyethylene glycol chain segment in the nucleating additive, the effect of an internal lubricant is achieved, the movement capability of the PET macromolecular chain is improved, the capability of the PET macromolecular chain to be folded around-COONa to form crystals is promoted, and the crystallization capability of the PET is improved.

Experiments show that when 99.2-91.0 parts of PET, 2.5 parts of sodium hydroxy polyethylene glycol carboxylate, 0.5 part of flow modifier, 0.5 part of release agent and 0.3 part of antioxidant are used, the crystallization rate of the PET can be obviously improved.

The invention provides a preparation method of the polyester special material for continuous fiber reinforcement, which comprises the steps of mixing raw materials, extruding, cooling, drawing, drying and granulating.

The specific method for mixing comprises the following steps: mixing at 50 deg.C under the rotation speed of 200 rpm of the stirrer for 1 hr, and cooling to room temperature.

The extrusion parameters affect the mixing uniformity of the polyester special material for continuous fiber reinforcement. In some embodiments, the extrusion parameters are 260 ℃ to 300 ℃, the main screw rotation speed is 50 rpm to 200 rpm, and the feed screw rotation speed is 5 rpm to 20 rpm.

In some embodiments, the mixture is mixed in a high-speed mixer for 30min, then the mixture is put into a hopper of an extruder and extruded under the conditions of 260-280 ℃ and the rotating speed of a main screw rod of 100 revolutions per minute and the rotating speed of a feeding screw rod of 12 revolutions per minute, and the extrudate is subjected to traction, cooling, drying and granulating to obtain the polyester special material for continuous fiber reinforcement.

In a fifth aspect of the invention, a continuous fiber reinforced PET composite material is provided, which comprises a reaction type nucleation additive and/or a polyester special material for continuous fiber reinforcement.

The invention provides a preparation method of the continuous fiber reinforced PET composite material, which comprises the steps of extruding and melting the special polyester material for continuous fiber reinforcement to obtain a PET molten pool, preheating continuous glass fibers, infiltrating resin into the PET molten pool, cooling, drawing, drying and granulating to obtain the continuous fiber reinforced PET composite material.

The special polyester material is placed into a hopper of an extruder, the melting is carried out under the conditions that the temperature is 270-290 ℃, the rotating speed of a main screw is 150 revolutions per minute and the rotating speed of a feeding screw is 30 revolutions per minute, the continuous glass fiber is preheated at 240 ℃, then the continuous glass fiber enters a PET molten pool to be soaked with resin, and the continuous fiber reinforced PET composite material is obtained through traction, cooling, drying and grain cutting.

The seventh aspect of the invention provides an application of a reaction type nucleating additive and/or a polyester special material for continuous fiber reinforcement in the preparation of a continuous fiber PET composite material.

In the eighth aspect of the invention, the composite fiber material comprises a reactive nucleating additive and/or a polyester special material for continuous fiber reinforcement and/or a continuous fiber reinforced PET composite material.

The present invention is described in further detail below with reference to specific examples, which are intended to be illustrative of the invention and not limiting.

Experimental example 1: as a comparison

Polyester PET (instrumented chemical fiber FG600), ionomer nucleating agent (DuPont Surlyn8920), flow modifier HyPer C181 (Wuhan branched resin technology Co., Ltd.), release agent AClyn 285A (U.S. Honeywell) and antioxidant 1098 (German BASF) are weighed according to parts by weight, wherein 96.2 parts of polyester, 2.5 parts of nucleating agent, 0.5 part of flow modifier, 0.5 part of release agent and 0.3 part of antioxidant are mixed in a high-speed mixer for 30min, then the mixture is put into an extruder hopper and extruded under the conditions of 260-280 ℃ and 100 r/min of main screw rotation speed and 12 r/min of feeding screw rotation speed, and the extrudate is subjected to traction, cooling, drying and granulation to obtain the special polyester material for continuous fiber reinforcement.

The special polyester material is placed into a hopper of an extruder, the melting is carried out under the conditions that the temperature is 270-290 ℃, the rotating speed of a main screw is 150 revolutions per minute and the rotating speed of a feeding screw is 30 revolutions per minute, the continuous glass fiber is preheated at 240 ℃, then the continuous glass fiber enters a PET molten pool to be soaked with resin, and the continuous fiber reinforced PET composite material is obtained through cooling, blow-drying, traction and grain cutting.

Example 2: the same as example 1, except that the sodium hydroxypolyethylene glycol carboxylate proposed by the present invention was used as a nucleating agent.

Firstly, preparing a reaction type nucleation additive, namely sodium hydroxy polyethylene glycol carboxylate, putting 1 mol of carboxyl hydroxy polyethylene glycol (with the molecular weight of 500 g/mol) and 0.9 mol of sodium hydroxide into a reactor, mixing for 1 hour at the temperature of 50 ℃ at the rotating speed of a stirrer of 200 revolutions per minute, and cooling to room temperature for later use. Weighing PET, sodium hydroxy polyethylene glycol carboxylate, a flow modifier, a release agent and an antioxidant according to parts by weight, wherein 95 parts of PET, 2.5 parts of sodium hydroxy polyethylene glycol carboxylate, 0.5 part of the flow modifier, 0.5 part of the release agent and 0.3 part of the antioxidant are mixed in a high-speed mixer for 30min, then putting the mixture into a hopper of an extruder, extruding at the temperature of 270 ℃ under the conditions that the rotating speed of a main screw is 100 revolutions per minute and the rotating speed of a feeding screw is 12 revolutions per minute, and cooling, blow-drying, drawing and granulating the extrudate to obtain the special material for the polyester for reinforcing the continuous fibers.

As shown in figure 1, the special material for polyester is placed in a feeding bin 1, the feeding quality is controlled by a weightless scale 2, and then the special material is placed in a hopper of a double-screw extruder 3, is melted at the conditions of the main screw rotating speed of 150 revolutions per minute and the feeding screw rotating speed of 30 revolutions per minute at 270 ℃, and enters a molten pool die head 6. Meanwhile, continuous glass fibers on the glass fiber raw material frame 4 are preheated in a preheating oven 5 at the preheating temperature of 240 ℃, enter a PET (polyethylene terephthalate) molten pool to be soaked with resin, sequentially pass through a cooling water tank 7, a blow-drying machine 8, a traction machine 9 and a granulator 10 to be granulated, and a vibrating screen 11 to sort the particle size, so that the continuous fiber reinforced PET composite material is obtained.

Example 3: the same as in example 2, except that the carboxyl hydroxypolyethylene glycol had a molecular weight of 1000 g/mol.

Example 4: the same as in example 2, except that the carboxyl hydroxy polyethylene glycol has a molecular weight of 2000 g/mol.

The test method comprises the following steps:

(1) DSC curve test method: the temperature is raised to 290 ℃ from room temperature at a speed of 10 ℃/min by adopting a relaxation-resistant DSC 214Polyma device, the temperature is kept for 5 min, then the temperature is lowered to room temperature at a speed of 10 ℃/min, a temperature-lowering curve is recorded, finally, the temperature is raised to 290 ℃ again at a speed of 10 ℃/min, and a temperature-raising curve is recorded.

(2) The mechanical property test method of the continuous fiber reinforced PET composite material comprises the following steps: the tensile strength is GBT1040.4-2006, and the notch impact strength is GBT 1043.1-2008.

TABLE 1 crystallization parameters of PET special-purpose material for continuous fiber reinforcement prepared in different examples

TABLE 2 mechanical Properties of continuous fiber reinforced PET composites prepared in different examples

As can be seen from the crystallization parameters of the PET special material for continuous fiber reinforcement shown in figure 1 and table 1, the sodium hydroxypolyethylene glycol carboxylate nucleating agent synthesized by the invention can remarkably improve the crystallization rate of PET, the crystallization period after the addition is reduced from 62.5 seconds of pure PET to minimum 8.41 seconds, and the cold crystallization peak temperature is reduced from 124 ℃ of pure PET to 98.02 ℃, as shown in example 3. The sodium hydroxy polyethylene glycol carboxylate integrates the nucleating agent and the crystallization accelerator, so the effect is better than that of singly adding the nucleating agent Surlyn 8920.

From Table 2 continuous fiber reinforced PET composite mechanicsThe performance can be seen that the continuous fiber reinforced composite material prepared by using the rapid crystallization PET as the raw material has better mechanical property, the highest tensile strength of the material reaches 243.11MPa, and the unnotched impact strength reaches 149.32kJ/m²The effect is also better than that of Surlyn8920, and the polyester composite material is very suitable for impregnating continuous fibers to prepare the polyester composite material.

As can be seen from FIG. 2, example 1 differs from example 2 in the presence or absence of the use of the reactive nucleating additive, the cold crystallization peak temperature was higher at 110.06 ℃ when the reactive nucleating additive was not used, and the cold crystallization peak temperature decreased significantly to 100.08 ℃ after the reactive nucleating additive was used in example 2.

The variable of examples 2-3 is the molecular weight of the reactive nucleating additive, and experiments show that the cold crystallization peak temperature is reduced and then increased along with the increase of the molecular weight of the reactive nucleating additive, and the cold crystallization peak of PET reaches the lowest 98.02 ℃ by adopting the reactive nucleating agent with the molecular weight of 1000 in example 3.

Although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that changes may be made in the embodiments and/or equivalents thereof without departing from the spirit and scope of the invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.