Glass fiber composite material for manufacturing special toe cap and preparation method thereof

Abstract

The invention relates to the technical field of special toe cap materials, in particular to a glass fiber composite material for manufacturing a special toe cap and a preparation method of the glass fiber composite material. The invention relates to a glass fiber composite material for manufacturing a special toe cap. The glass fiber composite material is prepared by hot-pressing multiple layers of glass fiber prepreg cloth; the glass fiber prepreg is prepared from the following raw materials in percentage by mass: 60 to 65 percent of glass fiber gridding cloth, 24 to 28 percent of thermosetting resin composition, 3 to 4 percent of low-shrinkage resin, 0.15 to 2 percent of initiator, 0.2 to 0.3 percent of cross-linking agent, 4 to 6 percent of heat-resistant reinforced monomer, 0.4 to 0.6 percent of thickening agent, 0.25 to 0.35 percent of defoaming agent and 0.8 to 1.2 percent of release agent. The special safety toe cap prepared from the glass fiber composite material provided by the invention is light in weight, meets the lightweight design requirement of safety shoes, has excellent compressive strength and impact strength, and meets the requirements of European standard EN 22568, standard CSA and American standard ASTM.

Description

Technical Field

[0001] This application relates to the technical field of special toe cap materials, and particularly to a glass fiber composite material for manufacturing special toe caps and a preparation method thereof. Background Art

[0002] Safety shoes are safety protection shoe products designed specifically for industrial and labor environments. They can effectively prevent heavy objects from hitting and sharp objects from piercing, protecting the toes from harm. They are applicable to various working environments such as construction sites, metallurgy, chemical synthesis, and pharmaceuticals, providing comprehensive safety protection for workers.

[0003] Safety shoes are usually equipped with special toe caps, which can be divided into metal toe caps or non-metal toe caps according to the type of toe caps. Among them, metal toe caps are usually steel toe caps, and very few are special aluminum alloy toe caps. Steel toe caps are simple to process and have relatively low production costs, making them the mainstream metal toe cap products. Although special aluminum alloy toe caps are light in texture, their production costs are relatively high, restricting their scope of use.

[0004] Plastic-steel toe caps can be divided into thermoplastic plastic-steel toe caps and thermosetting plastic-steel toe caps according to different resin matrices. Thermoplastic plastic-steel toe caps have relatively simple production processes and lower production costs compared to thermosetting plastic-steel toe caps. However, their relatively low compressive strength restricts their application scope. Although the dense three-dimensional network structure of thermosetting plastic-steel toe caps endows them with good compressive strength, their impact resistance is relatively low, they are prone to brittle fracture under impact, and their service life is relatively short, increasing the production cost of safety shoes invisibly.

[0005] To solve the problem that the impact resistance, compressive strength, and lightweight of the existing safety shoe toe caps cannot be achieved simultaneously, the inventor provides a glass fiber composite material for manufacturing special toe caps and a preparation method thereof. Summary of the Invention

[0006] To solve the technical bottleneck that the impact resistance, compressive strength, and lightweight cannot be achieved simultaneously in the above-mentioned technology, the present invention provides a glass fiber composite material for manufacturing special toe caps and a preparation method thereof.

[0007] The glass fiber composite material for manufacturing special toe caps provided by the present invention is achieved through the following technical solutions: A glass fiber composite material for manufacturing special toe caps is hot-pressed from multiple layers of glass fiber prepreg. The glass fiber prepreg is made from the following raw materials in mass percentages: 60 - 65 wt% of glass fiber mesh cloth, 24 - 28 wt% of thermosetting resin composition, 3.0 - 4.0 wt% of low shrinkage resin, 0.15 - 2.0 wt% of initiator, 0.20 - 0.30 wt% of crosslinking agent, 4.0 - 6.0 wt% of heat-resistant reinforcing monomer, 0.4 - 0.6 wt% of thickening agent, 0.25 - 0.35 wt% of defoaming agent, 0.8 - 1.2 wt% of mold release agent; The glass fiber mesh cloth is surface-modified with a silane coupling agent and then impregnated in an interface-modifying resin, dried and cured; the interface-modifying resin is isocyanate-modified hydroxypropyl acrylate resin; The thermosetting resin composition at least includes acrylate resin and hydroxy acrylate resin.

[0008] The special plastic-steel shoe toe prepared by the present invention is not only light in texture, meeting the lightweight design requirements of shoe products, but also has excellent compressive strength and impact strength, and has a relatively wide range of applications, and can be applied to shoe products such as safety shoes, labor protection shoes, work shoes, and hiking shoes.

[0009] Preferably, the thermosetting resin composition is made from the following raw materials in mass percentages: 63 - 64 wt% of glass fiber mesh cloth, 26 - 27 wt% of thermosetting resin composition, 3.2 - 3.5 wt% of low shrinkage resin, 0.18 - 2.0 wt% of initiator, 0.24 - 0.26 wt% of crosslinking agent, 4.0 - 4.2 wt% of heat-resistant reinforcing monomer, 0.5 - 0.54 wt% of thickening agent, 0.30 - 0.32 wt% of defoaming agent, 1.0 - 1.1 wt% of mold release agent.

[0010] Optimizing the formula of the thermosetting resin composition can ensure the compressive strength, impact strength, and lightweight design requirements of the special plastic-steel shoe toe, and at the same time can optimize the production cost of the special plastic-steel shoe toe and enhance the market competitiveness of the product.

[0011] Preferably, the thermosetting resin composition is composed of propyl methacrylate, polyethylene glycol methyl ether methacrylate with a number average molecular weight of 400 - 1000, and hydroxy-terminated polysiloxane modified with side-chain acrylate with a number average molecular weight of 800 - 2000.

[0012] Preferably, the mass ratio of propyl methacrylate, polyethylene glycol methyl ether methacrylate with a number average molecular weight of 400 - 1000, and hydroxy-terminated polysiloxane modified with side-chain acrylate with a number average molecular weight of 800 - 2000 is (80 - 100):(5 - 30):(5 - 20).

[0013] By optimizing the composition of the thermosetting resin composition, the compressive strength of the plastic-steel special shoe head can be ensured while further optimizing and improving the impact strength of the plastic-steel special shoe head.

[0014] Preferably, the side chain acrylate modified hydroxyl-terminated polysiloxane includes γ-methacryloxypropylmethyldimethoxysilane, dimethoxymethylpropyl silane, methylphenyldimethoxysilane, and trimethoxy(methyl)silane capping.

[0015] Preferably, the molar ratio of the γ-methacryloxypropylmethyldimethoxysilane, dimethoxymethylpropylsilane and methylphenyldimethoxysilane is (1-2):5:(1-2).

[0016] By adopting the above technical solution, the heat-resistant stability of plastic-steel special shoe heads can be improved, thereby expanding the application scope of plastic-steel special shoe heads. The thermosetting resin composition can be flexibly designed according to the actual application scenarios to meet the usage requirements of different application scenarios, thereby enhancing the core competitiveness of the enterprise.

[0017] Preferably, the preparation method of the side chain acrylate modified hydroxyl-terminated polysiloxane is as follows: 10 parts by weight of γ-methacryloxypropylmethyldimethoxysilane, 0.05-0.20 parts by weight of hydroquinone, a polymerization inhibitor, and 20-30 parts by weight of an aqueous solution are uniformly mixed, an acid solution is added to adjust the pH value to 5-6.5, and an alcoholysis reaction is carried out at 40-60° C. for 15-60 minutes to obtain a silanol mixed solution A; 10 parts by weight of dimethoxymethylpropylsilane and 20-30 parts by weight of aqueous solution are uniformly mixed, acid solution is added to adjust the pH value to 5-6.5, and alcoholysis reaction is carried out at 40-60° C. for 15-60 minutes to obtain a silanol mixed solution B; 10 parts by weight of methylphenyldimethoxysilane and 20-30 parts by weight of an aqueous solution are uniformly mixed, an acid solution is added to adjust the pH value to 5-6.5, and an alcoholysis reaction is carried out at 40-60° C. for 15-60 minutes to obtain a silanol mixed solution C; Transfer the silanol mixture B to a three-necked flask, heat it to 35-45°C in a water bath, and add silanol mixture A and silanol mixture C dropwise at 80-160rpm under magnetic stirring. The dropping speed of silanol mixture A is 1-5mL / min, and the dropping speed of silanol mixture C is 1-5mL / min. After the dropping of silanol mixture A and silanol mixture C is completed, the temperature is maintained at 35-45°C for 60-90min, and then dimethoxydimethylsilane and acid solution are added to adjust the pH value to 5-6 for end-capping reaction for 5-10min. After adding alkali solution to adjust the pH value to 7, the mixture enters a water separator for dehydration treatment, and then the obtained liquid is subjected to reduced pressure fractionation to remove the hydrolyzed silane monomers that do not participate in the reaction, so as to obtain side chain acrylate-modified hydroxyl-terminated polysiloxane.

[0018] Preferably, the molar ratio of hydrolyzed γ-methacryloxypropylmethyldimethoxysilane in the silicon alcohol mixture A, hydrolyzed dimethoxymethylpropylsilane in the silicon alcohol mixture B, and hydrolyzed methylphenyldimethoxysilane in the silicon alcohol mixture C is (1 - 4):10:(1 - 2).

[0019] The preparation method of the side-chain acrylate-modified hydroxyl-terminated polysiloxane provided in the present invention is relatively simple, with relatively low operation difficulty. It can be synthesized by the laboratory itself or commissioned to enterprises for industrial mass production and customization.

[0020] By adopting the above technical solution, the compressive strength and impact resistance of the special plastic-steel shoe toe can be improved.

[0021] Preferably, the cross-linking agent is at least one of dipropylene glycol diacrylate, trimethylolpropane triacrylate, HDI trimer curing agent, and pentaerythritol triacrylate.

[0022] By adopting the above technical solution, the compressive strength and impact resistance of the special plastic-steel shoe toe can be improved.

[0023] Preferably, the low-shrinkage resin is polycaprolactone NPG200.

[0024] Preferably, the heat-resistant reinforcing monomer is at least one of styrene and stilbene.

[0025] By adopting the above technical solution, it is beneficial to improve the high-temperature service performance of the special plastic-steel shoe toe.

[0026] Preferably, the initiator is at least one of benzoyl peroxide BPO, tert-butyl peroxy-2-ethylhexanoate TBPO, azobisisobutyronitrile AIBN, tetraisopropyl titanate, and dibutyltin dilaurate.

[0027] Preferably, the initiator is a composition of benzoyl peroxide BPO and tetraisopropyl titanate.

[0028] Tetraisopropyl titanate composition can catalyze the polyurethane reaction of organic substances containing -NCO groups and organic substances containing active -OH, meet the requirement of pre-curing into a gel film state in step two to obtain a thermosetting resin composition film, and facilitate the improvement of the overall processing performance; benzoyl peroxide BPO meets the high-temperature initiation of double-bond polymerization reaction in the hot pressing and forming stage in step four, and hot curing and forming to produce high-quality special plastic-steel shoe toes.

[0029] Preferably, the thickener is at least one of magnesium oxide, fumed silica, organic bentonite, and montmorillonite.

[0030] By adopting the above technical solution, the viscosity of the thermosetting resin composition can be adjusted, which is convenient for the preparation of the finished glass fiber prepreg in the later preparation process stage and is conducive to improving the overall processing performance.

[0031] Preferably, the defoaming agent is BASF Efka PB 2720 defoaming agent or BYK 051N defoaming agent.

[0032] By adopting the above technical solution, excellent defoaming treatment is achieved, the density of the special plastic-steel shoe toe can be improved, and further the compressive strength and impact strength of the special plastic-steel shoe toe can be improved.

[0033] Preferably, the mold release agent is at least one of stearate, molybdenum disulfide, talcum powder, and mica powder.

[0034] By adopting the above technical solution, it is convenient to achieve rapid demolding after the thermosetting hot pressing molding is completed, improve the overall processing performance, and is conducive to improving the surface smoothness of the special plastic-steel shoe toe and enhancing the product appearance.

[0035] The preparation method of a glass fiber composite material for manufacturing a special shoe toe provided by the present invention is realized through the following technical solutions: A preparation method of a glass fiber composite material for manufacturing a special shoe toe includes the following steps: Step 1, preparation of pretreatment of the glass fiber grid cloth; meanwhile, prepare the thermosetting resin composition; Step 2, mix the accurately metered thermosetting resin composition, low shrinkage resin, initiator, crosslinking agent, heat-resistant reinforcing monomer, thickening agent, defoaming agent, and mold release agent evenly to obtain a film-forming slurry. Coat the obtained film-forming slurry evenly on the surface of the release paper, and perform pre-curing treatment on the film-forming slurry on the surface of the release paper until the film-forming slurry is in a gel film state to obtain a thermosetting resin composition film. Step 3, attach two obtained thermosetting resin composition films to the upper and lower surfaces of the glass fiber prepreg to obtain the glass fiber prepreg. The glass fiber prepreg is cured at 40 - 50 °C for 36 - 48 h; Step 4, cut the cured glass fiber prepreg to obtain a finished glass fiber prepreg in the shape of a molding die. The finished glass fiber prepreg is stacked into a preformed shoe toe by the manual lamination method. After hot pressing molding, demold, trim, and polish to obtain a finished plastic-steel shoe toe. The hot pressing molding parameters are as follows: first pressurize to 10 - 20 MPa at 0.5 - 1 MPa / s, keep the pressure for 60 ± 5 s at a hot pressing temperature of 120 - 130 °C, then pressurize to 30 - 40 MPa at 2 - 2.5 MPa / s, and keep the pressure for 120 ± 5 s at a hot pressing temperature of 140 - 160 °C.

[0036] The preparation method of the present invention is relatively simple, with low operation difficulty, and is convenient for realizing industrialized mass production.

[0037] Preferably, the preparation method of the pretreatment of the fiberglass mesh cloth in the first step is as follows: First, spray an aqueous solution of methacryloxy silane on the surface of the fiberglass mesh cloth. The concentration of methacryloxy silane in the aqueous solution of methacryloxy silane is 4-8 wt%, and the spraying amount is 5-40 g / m 2 , then input it into an oven for drying treatment. The drying temperature is 50-70 °C, and the drying time is 5-10 min. Finally, scrape and coat isocyanate-modified hydroxypropyl acrylate resin on the surface of the methacryloxy silane-modified fiberglass mesh cloth. The scraping amount is 5-50 g / m 2 , pre-cure and form at 60-75 °C for 15-20 min, and then compound with release paper, and wind it up to obtain the finished fiberglass mesh cloth.

[0038] Grafting methacryloxy silane on the surface of the fiberglass mesh cloth improves its compatibility with isocyanate-modified hydroxypropyl acrylate resin, enabling the isocyanate-modified hydroxypropyl acrylate resin to be evenly coated on the surface of the methacryloxy silane-modified fiberglass mesh cloth. The -NCO groups in the isocyanate-modified hydroxypropyl acrylate resin will react with the exposed active -OH groups on the surface of the fiberglass mesh cloth in a polyurethane reaction, and the -NCO groups in the isocyanate-modified hydroxypropyl acrylate resin will react with the terminal hydroxyl -OH groups in the methacryloxy silane oligomer in a polyurethane reaction. After pre-curing and forming at 60-75 °C for 15-20 min, it becomes a gel state and is compounded with release paper.

[0039] The preparation method of the finished fiberglass prepreg in the present invention is relatively simple, convenient for realizing mass production, reducing the production cost of the finished fiberglass prepreg, and the prepared finished fiberglass prepreg is convenient for subsequent processing and use, improving the production efficiency and product quality stability of the same batch of plastic-steel special shoe tips.

[0040] In summary, the present application has the following advantages: 1. The plastic-steel special shoe tip prepared by the present invention is not only light in texture, meeting the lightweight design requirements of shoe products, but also has excellent compressive strength and impact strength.

[0041] 2. The preparation method of the present invention is relatively simple, with low operation difficulty, and is convenient for realizing industrialized mass production.

[0042] 3. The plastic-steel safety shoe tip prepared by using the fiberglass composite material provided in the present invention has a relatively high weight ratio. Compared with a steel shoe tip, when the strength is the same, the weight of the plastic-steel safety shoe tip is about 50% of that of the steel shoe tip, reducing the overall weight of the safety shoe, facilitating the lightweight design of the safety shoe, and meeting the requirements of hiking shoes.

[0043] 4. The plastic-steel safety toe cap product of the present invention has a high degree of design freedom. According to different designed molds, a plastic-steel toe cap with uneven thickness and streamline shape can be designed and manufactured, and it has a high surface finish and better appearance.

[0044] 5. The plastic-steel safety toe cap prepared by using the glass fiber composite material provided in the present invention has the advantages of insulation safety, impact resistance, high and low temperature resistance, corrosion resistance, and good chemical stability.

[0045] 6. The preparation process of the present invention is a thermosetting process, and the material is non-toxic, meeting the trend of green environmental protection.

[0046] 7. The plastic-steel safety toe cap prepared by using the glass fiber composite material provided in the present invention is a non-metallic material, non-conductive, with good insulation performance, and can pass airport security checks, expanding its application scope.

[0047] 8. The plastic-steel safety toe cap prepared by using the glass fiber composite material provided in the present invention has a relatively wide application scope and can be applied to shoe products such as safety shoes, labor protection shoes, work shoes, and hiking shoes. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 is a schematic structural diagram of the glass fiber plastic-steel toe cap prepared in Example 1 of the present invention.

[0049] Figure 2 is a process flow chart of the glass fiber plastic-steel toe cap in Example 1 of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0050] In order to further understand the creativity and technological progress of the present invention, the preferred implementation schemes of the present invention will be described in detail below in combination with examples and comparative examples. It should be noted that: this specific embodiment is only an explanatory illustration of the technical solution of the present invention, and it is not a limitation of the present invention. Those skilled in the art can make modifications without creative contributions to this embodiment according to needs after reading this specification, but as long as it is within the scope of the claims of the present invention, it is protected by the patent law.

[0051] Example: A glass fiber composite material for manufacturing special toe caps is made by stacking multiple layers of glass fiber prepreg into a preformed pre-product toe cap through the manual lamination method, and then demolding, trimming, and polishing the preformed pre-product toe cap after hot pressing.

[0052] The glass fiber prepreg contained in the glass fiber plastic-steel toe cap made of the glass fiber composite material can ensure that the glass fiber plastic-steel toe cap has excellent compressive strength and impact strength, and meets the requirements of lightweight design. The density of the glass fiber composite material used for manufacturing special toe caps is less than 2.2 g / cm 3。In the above fiberglass composite material, the bonding strength between the fiberglass mesh cloth and the thermosetting resin composition matrix is particularly important. The quality of the bonding strength determines the compressive strength and impact resistance of the fiberglass safety toe product.

[0053] For this reason, the inventor has developed a fiberglass mesh cloth with special surface treatment, specifically as follows. The fiberglass mesh cloth is first surface-modified with a silane coupling agent, and then impregnated in an interface-modifying resin, dried and cured. The interface-modifying resin is isocyanate-modified hydroxypropyl acrylate resin. Under the action of medium and low temperature (60 - 80 °C) and tetra-isopropyl titanate and / or dibutyltin dilaurate, the -NCO group of the isocyanate-modified hydroxypropyl acrylate resin reacts with the active hydroxyl group -OH in the thermosetting resin composition to produce a polyurethane group -NH-CO- connecting molecular unit to complete the preliminary connection with the thermosetting resin composition. Then, in the thermoforming process, at high temperature (100 - 140 °C) and with at least one of benzoyl peroxide BPO, tert-butyl peroxy-2-ethylhexanoate TBPO, and azobisisobutyronitrile AIBN as initiators, the double bonds of the entire isocyanate-modified hydroxypropyl acrylate resin undergo a double bond polymerization reaction with the double bonds in the thermosetting resin composition, thereby effectively improving the crosslinking density of the polymer and further improving the compressive strength and impact resistance of the fiberglass safety toe product.

[0054] The isocyanate-modified hydroxypropyl acrylate resin is composed of HDI isocyanate and propyl methacrylate.

[0055] The fiberglass mesh cloth is selected as EWR600 with a grammage of 600 g / m 2 。

[0056] For the specific preparation method of the fiberglass mesh cloth, refer to the preparation method of the fiberglass mesh cloth in Example 1.

[0057] The thermosetting resin composition has a significant impact on the density, compressive strength, and impact resistance of the fiberglass safety toe. The present invention has optimized the design of the thermosetting resin composition.

[0058] Specifically, the thermosetting resin composition is composed of propyl methacrylate, polyethylene glycol methyl ether methacrylate with a number average molecular weight of 400 - 1000, and a hydroxyl-terminated polysiloxane modified with side-chain acrylate with a number average molecular weight of 800 - 2000.

[0059] The compound use of polyethylene glycol methyl ether methacrylate can improve and enhance the impact resistance of the special plastic-steel safety toe, and enhance the toughness and impact resilience recovery performance of the special plastic-steel safety toe.

[0060] The side-chain acrylate-modified hydroxyl-terminated polysiloxane can improve and enhance the impact resistance of the special plastic-steel safety toe, enhance the toughness and impact resilience recovery performance of the special plastic-steel safety toe. In addition, it can also improve the high-temperature service performance of the special plastic-steel safety toe.

[0061] Preferably, the mass ratio of propyl methacrylate, polyethylene glycol methyl ether methacrylate with a number-average molecular weight of 400 - 1000, and side-chain acrylate-modified hydroxyl-terminated polysiloxane with a number-average molecular weight of 800 - 2000 is (80 - 100):(5 - 30):(5 - 20). And the total mass of polyethylene glycol methyl ether methacrylate with a number-average molecular weight of 400 - 1000 and side-chain acrylate-modified hydroxyl-terminated polysiloxane with a number-average molecular weight of 800 - 2000 to the mass of propyl methacrylate is (25 - 50):100.

[0062] The fiberglass prepreg is made from the following raw materials by mass percentage: 60 - 65 wt% of fiberglass mesh cloth, 24 - 28 wt% of thermosetting resin composition, 3.0 - 4.0 wt% of low-shrinkage resin, 0.15 - 2.0 wt% of initiator, 0.20 - 0.30 wt% of crosslinking agent, 4.0 - 6.0 wt% of heat-resistant reinforcing monomer, 0.4 - 0.6 wt% of thickener, 0.25 - 0.35 wt% of defoaming agent, 0.8 - 1.2 wt% of mold release agent.

[0063] The fiberglass mesh cloth is new fiberglass mesh cloth or recycled fiberglass mesh cloth.

[0064] The crosslinking agent in the fiberglass prepreg formulation affects the overall crosslinking density of the composite material. Preferably, the crosslinking agent is at least one of dipropylene glycol diacrylate, trimethylolpropane triacrylate, HDI trimer curing agent, and pentaerythritol triacrylate.

[0065] In order to improve the production efficiency of the fiberglass composite material, dipropylene glycol diacrylate, trimethylolpropane triacrylate, and pentaerythritol triacrylate contained in the crosslinking agent are photosensitive monomers, which facilitate the pre-curing of the thermosetting resin composition into a gel film state in step two of the processing stage to obtain a thermosetting resin composition film.

[0066] The -NCO group in the HDI trimer curing agent contained in the crosslinking agent can react with the -OH group in propyl methacrylate in the thermosetting resin composition to generate a polyurethane group -NH-CO- to connect molecular units, which facilitates the pre-curing of the thermosetting resin composition into a gel film state in the processing stage to obtain a thermosetting resin composition film.

[0067] The low-shrinkage resin is polycaprolactone NPG200, which improves the low shrinkage of the hot pressing molding of the plastic-steel shoe toe.

[0068] The heat-resistant reinforcing monomer is at least one of styrene and stilbene, preferably styrene.

[0069] The initiator is at least one of benzoyl peroxide (BPO), tert-butyl peroxy-2-ethylhexanoate (TBPO), azobisisobutyronitrile (AIBN), tetra-isopropyl titanate, and dibutyltin dilaurate.

[0070] The initiator is prepared by compounding benzoyl peroxide (BPO) and tetra-isopropyl titanate.

[0071] The thickener is at least one of magnesium oxide, fumed silica, organobentonite, and montmorillonite. Preferably, the thickener is magnesium oxide, which can achieve a good thickening effect while optimizing the overall production cost.

[0072] The defoamer is BASF Efka PB 2720 defoamer or BYK 051N defoamer.

[0073] The mold release agent is at least one of stearate, molybdenum disulfide, talcum powder, and mica powder.

[0074] The side-chain acrylate-modified hydroxyl-terminated polysiloxane is mainly made of γ-methacryloxypropylmethyldimethoxysilane, dimethoxymethylpropylsilane, and methylphenyldimethoxysilane.

[0075] The side-chain acrylate-modified hydroxyl-terminated polysiloxane has the effect of improving the impact strength of the fiberglass safety toe in the thermosetting resin composition. The improvement of the impact strength is mainly reflected in the optimization of toughness and impact resilience recovery performance. In addition, it can also improve the high-temperature service performance of the fiberglass safety toe.

[0076] The structural formula of the side-chain acrylate-modified hydroxyl-terminated polysiloxane is as follows: , where the molar ratio of a:b:c = 5:(1 - 2):(1 - 2). That is, in the preparation process of the side-chain acrylate-modified hydroxyl-terminated polysiloxane, preferably, the molar ratio of γ-methacryloxypropylmethyldimethoxysilane, dimethoxymethylpropylsilane, and methylphenyldimethoxysilane is (1 - 2):5:(1 - 2).

[0077] Controlling the addition amount of methylphenyldimethoxysilane can adjust the number of benzene rings on the polysiloxane side chain, and thus can improve the heat resistance and compressive strength of the plastic-steel toe.

[0078] Controlling the addition amount of γ-methacryloxypropylmethyldimethoxysilane can adjust the number of γ-methacryloxy groups on the polysiloxane side chain, that is, control the double bond content, and then control the crosslinking density of the three-dimensional network structure of the formed cured product. It can improve the heat resistance and compressive strength of the fiberglass safety toe and at the same time endow it with good impact strength, so that the fiberglass safety toe meets the requirements of European standard EN22568, Canadian standard CSA, and American standard ASTM.

[0079] In the thermosetting resin composition, the addition amount of the side-chain acrylate-modified hydroxyl-terminated polysiloxane should not be too much. Excessive addition of the side-chain acrylate-modified hydroxyl-terminated polysiloxane will lead to too high a crosslinking density of the three-dimensional network structure of the formed cured product, increasing brittleness and decreasing toughness, with poor impact toughness.

[0080] See Figure 2 , a preparation method of a glass fiber composite material for manufacturing a special shoe tip, comprising the following steps: Step 1, preparation of pretreatment of the glass fiber grid cloth; At the same time, prepare a thermosetting resin composition; Step 2, put the accurately metered thermosetting resin composition, low-shrinkage resin, heat-resistant reinforcing monomer, thickener, defoaming agent, and demolding agent into a reaction kettle, stir and defoam under nitrogen protection for 30 - 45 min. After defoaming is completed, add an initiator and a crosslinking agent and mix evenly to obtain a film-forming slurry. Coat the obtained film-forming slurry evenly on the surface of the release paper, and perform precuring treatment on the film-forming slurry on the surface of the release paper until the film-forming slurry is in a gel film state to obtain a thermosetting resin composition film; Step 3, laminate two obtained thermosetting resin composition films on the upper and lower surfaces of the glass fiber prepreg to obtain a glass fiber prepreg. The glass fiber prepreg is cured at 40 - 50 °C for 36 - 48 h; Step 4, cut the cured glass fiber prepreg to obtain a finished glass fiber prepreg in the shape of a molding die. The finished glass fiber prepreg is stacked into a preformed shoe tip by the manual lamination method. After hot pressing and forming, demold, trim, and polish to obtain a finished plastic-steel shoe tip. The hot pressing and forming parameters are as follows: first pressurize to 10 - 20 MPa at 0.5 - 1 MPa / s, hold the pressure for 60 ± 5 s at a hot pressing temperature of 120 - 130 °C, then pressurize to 30 - 40 MPa at 2 - 2.5 MPa / s, and hold the pressure for 120 ± 5 s at a hot pressing temperature of 140 - 160 °C to obtain a glass fiber safety shoe tip. For the physical product of the glass fiber safety shoe tip, see specifically Figure 1 .

[0081] Preparation Example 1: The preparation method of the side-chain acrylate-modified hydroxyl-terminated polysiloxane is as follows: Step 1, mix 23.3 g of γ-methacryloxypropylmethyldimethoxysilane KH572 (CAS No.: 3978-58-3) 0, 0.12 g of inhibitor - hydroquinone (CAS No.: 123-31-9) with 50 g of aqueous solution evenly, adjust the pH value to 6.0 by adding 0.1 mol / L dilute hydrochloric acid, and carry out alcoholysis reaction at 45 °C for 30 min to obtain a silanol mixed solution A by hydrolyzing KH572; Mix 14.8 g of dimethoxymethylpropylsilane (CAS No. 18173-73-4) evenly with 30 g of aqueous solution, add dilute hydrochloric acid with a concentration of 0.1 mol / L to adjust the pH value to 6.0, and carry out an alcoholysis reaction of dimethoxymethylpropylsilane at 45 °C for 30 min to obtain a silanol mixture B; Mix 18.2 g of methylphenyldimethoxysilane (CAS No. 3027-21-2) evenly with 40 g of aqueous solution, add dilute hydrochloric acid with a concentration of 0.1 mol / L to adjust the pH value to 6.0, and carry out an alcoholysis reaction at 45 °C for 30 min to obtain a silanol mixture C; Step 2: Transfer 224.0 g of the silanol mixture B to a 1000 ml three-necked flask, heat it in a water bath to 40 °C, and while stirring magnetically at 120 rpm, simultaneously add 73.3 g of the silanol mixture A and 58.2 g of the silanol mixture C. The dropping rate of the silanol mixture A is 1.8 mL / min, and the dropping rate of the silanol mixture C is 1.5 mL / min. After the dropping of the silanol mixture A and the silanol mixture C is completed, continue the reaction at 40 °C for 60 min, then add 3.1 g of dimethoxydimethylsilane (CAS No. 1112-39-6) and stir magnetically at 120 rpm for 2 min. Add dilute hydrochloric acid with a concentration of 0.1 mol / L to adjust the pH value to 5.5 for end-capping reaction for 400 s, and then add an aqueous solution of NaOH with a concentration of 0.1 mol / L to adjust the pH value to 7. Pour the obtained liquid material from the three-necked flask into a water separator for dehydration treatment, and pour the dehydrated polysiloxane mixture into a three-necked flask equipped with a distillation head for vacuum fractional distillation to remove low-boiling materials (unreacted hydrolyzed silane monomers), and then the side-chain acrylate-modified hydroxyl-terminated polysiloxane can be obtained.

[0082] The number-average molecular weight of the prepared side-chain acrylate-modified hydroxyl-terminated polysiloxane was measured by the vapor pressure (gas phase) osmometry method. The number-average molecular weight of the side-chain acrylate-modified hydroxyl-terminated polysiloxane was 720, and the parameter D of the molecular weight distribution width was 1.24.

[0083] What needs to be controlled in Step 2 is the dropping amount of the silanol mixture A and the silanol mixture C. The limiting conditions are as follows: the molar ratio of hydrolyzed γ-methacryloxypropylmethyldimethoxysilane in the silanol mixture A, hydrolyzed dimethoxymethylpropylsilane in the silanol mixture B, and hydrolyzed methylphenyldimethoxysilane in the silanol mixture C is 1:5:1.

[0084] The difference between Preparation Example 2 and Preparation Example 1 lies in the following: In Step 2, 224.0 g of silanol mixture B was transferred to a 1000 ml three-necked flask, heated in a water bath to 40 °C, and while stirring magnetically at 120 rpm, 146.6 g of silanol mixture A and 58.2 g of silanol mixture C were simultaneously added dropwise. The dropping rate of silanol mixture A was 1.8 mL / min, and the dropping rate of silanol mixture C was 1.5 mL / min. After the addition of silanol mixture A and silanol mixture C was completed, the reaction was continued at 40 °C for 75 min. Then, 3.1 g of dimethoxydimethylsilane (CAS No. 1112-39-6) was added and stirred magnetically at 120 rpm for 2 min. The pH value was adjusted to 5.5 with 0.1 mol / L dilute hydrochloric acid for end-capping reaction for 400 s, and then the pH value was adjusted to 7 with 0.1 mol / L aqueous NaOH solution. The resulting liquid material was poured from the three-necked flask into a water separator for dehydration treatment. The dehydrated polysiloxane mixture was poured into a three-necked flask equipped with a distillation head for vacuum fractional distillation to remove low-boiling materials - unreacted hydrolyzed silane monomers, and thus the hydroxyl-terminated polysiloxane modified with side-chain acrylate was obtained.

[0085] The number-average molecular weight of the prepared hydroxyl-terminated polysiloxane modified with side-chain acrylate was measured by the vapor pressure (gas phase) osmometry method. The number-average molecular weight of the hydroxyl-terminated polysiloxane modified with side-chain acrylate was 885, and the parameter D of the molecular weight distribution width was 1.27.

[0086] What needs to be controlled in Step 2 is the dropping amount of silanol mixture A and silanol mixture C. The limiting conditions are as follows: The molar ratio of hydrolyzed γ-methacryloxypropylmethyldimethoxysilane in silanol mixture A, hydrolyzed dimethoxymethylpropylsilane in silanol mixture B, and hydrolyzed methylphenyldimethoxysilane in silanol mixture C is 2:5:1.

[0087] The difference between Preparation Example 3 and Preparation Example 1 lies in the following: In Step 2, 224.0 g of silanol mixture B was transferred to a 1000 ml three-necked flask, heated in a water bath to 40 °C, and while stirring magnetically at 120 rpm, 146.6 g of silanol mixture A and 116.4 g of silanol mixture C were simultaneously added dropwise. The dropping rate of silanol mixture A was 1.8 mL / min, and the dropping rate of silanol mixture C was 1.5 mL / min. After the addition of silanol mixture A and silanol mixture C was completed, the reaction was continued at 40 °C for 90 min. Then, 3.1 g of dimethoxydimethylsilane (CAS No. 1112-39-6) was added and stirred magnetically at 120 rpm for 2 min. The pH value was adjusted to 5.5 with 0.1 mol / L dilute hydrochloric acid for end-capping reaction for 400 s, and then the pH value was adjusted to 7 with 0.1 mol / L aqueous NaOH solution. The obtained liquid material was poured from the three-necked flask into a water separator for dehydration treatment. The dehydrated polysiloxane mixture was poured into a three-necked flask equipped with a distillation head for vacuum fractional distillation to remove low-boiling materials - unreacted hydrolyzed silane monomers, and thus the hydroxyl-terminated polysiloxane modified with side-chain acrylate was obtained.

[0088] The number-average molecular weight of the prepared hydroxyl-terminated polysiloxane modified with side-chain acrylate was measured by the vapor pressure (gas phase) osmometry method. The number-average molecular weight of the hydroxyl-terminated polysiloxane modified with side-chain acrylate was 1052, and the parameter D of the molecular weight distribution width was 1.31.

[0089] In Step 2, what needs to be controlled is the dropping amount of silanol mixture A and silanol mixture C, and the limiting conditions are as follows: The molar ratio of hydrolyzed γ-methacryloxypropylmethyldimethoxysilane in silanol mixture A, hydrolyzed dimethoxymethylpropylsilane in silanol mixture B, and hydrolyzed methylphenyldimethoxysilane in silanol mixture C is 2:5:2.

[0090] Preparation Example 4: The preparation method of the hydroxyl-terminated polysiloxane modified with side-chain acrylate is as follows: Step 1, 23.3 g of γ-methacryloxypropylmethyldimethoxysilane KH572 (CAS No.: 3978-58-3), 0.12 g of inhibitor - hydroquinone (CAS No.: 123-31-9) were mixed evenly with 50 g of aqueous solution, and the pH value was adjusted to 6.0 with 0.1 mol / L dilute hydrochloric acid, and alcoholysis reaction was carried out at 45 °C for 30 min to obtain silanol mixture A by hydrolyzing KH572; 14.8 g of dimethoxymethylpropylsilane (CAS No. 18173-73-4) was mixed evenly with 30 g of aqueous solution, and the pH value was adjusted to 6.0 with 0.1 mol / L dilute hydrochloric acid, and dimethoxymethylpropylsilane was subjected to alcoholysis reaction at 45 °C for 30 min to obtain silanol mixture B; Step 2: Transfer 224.0 g of silanol mixture B into a 1000 ml three-necked flask, heat it in a water bath to 40 °C, and while stirring magnetically at 120 rpm, simultaneously add 146.6 g of silanol mixture A dropwise. The dropping rate of silanol mixture A is 1.8 mL / min. After the addition of silanol mixture A is completed, continue the reaction at 40 °C for 60 min. Then add 3.1 g of dimethoxydimethylsilane (CAS No. 1112-39-6) and stir magnetically at 120 rpm for 2 min. Add dilute hydrochloric acid with a concentration of 0.1 mol / L to adjust the pH value to 5.5 for end-capping reaction for 400 s, and then add an aqueous solution of NaOH with a concentration of 0.1 mol / L to adjust the pH value to 7. Pour the obtained liquid material from the three-necked flask into a water separator for dehydration treatment. Pour the dehydrated polysiloxane mixture into a three-necked flask equipped with a distillation head for vacuum fractional distillation to remove low-boiling materials - unreacted hydrolyzed silane monomers, and then the hydroxyl-terminated polysiloxane modified with side-chain acrylate can be obtained.

[0091] The number-average molecular weight of the prepared hydroxyl-terminated polysiloxane modified with side-chain acrylate was measured by the vapor pressure (gas phase) osmometry method. The number-average molecular weight of the hydroxyl-terminated polysiloxane modified with side-chain acrylate was 786, and the parameter D of the molecular weight distribution width was 1.27.

[0092] In Step 2, what needs to be controlled is the dropping amount of silanol mixture A, and the limiting conditions are as follows: the molar ratio of hydrolyzed γ-methacryloxypropylmethyldimethoxysilane in silanol mixture A to hydrolyzed dimethoxymethylpropylsilane in silanol mixture B is 2:5.

[0093] Example 1: A glass fiber composite material for manufacturing special shoe tips is made by hot pressing multiple layers of glass fiber prepregs. The formula of the glass fiber prepreg is as follows: 637.60 g of surface-modified EWR600 glass fiber mesh cloth (thickness 600 ± 10 μm, warp density 2.50 ± 0.25 threads / cm, weft density 2.50 ± 0.25 threads / cm, width 1000 mm); 186.90 g of propyl methacrylate (CAS No.: 2210-28-8); 44.0 g of methoxypolyethylene glycol methacrylate MPEG 1000MA (CAS No.: 26915-72-0); 33.0 g of the hydroxyl-terminated polysiloxane modified with side-chain acrylate synthesized in Preparation Example 1; 33.0 g of low-shrinkage resin - polycaprolactone NPG200; 1.10 g of benzoyl peroxide BPO (CAS No.: 94-36-0); 0.88 g of tetra-isopropyl titanate (CAS No.: 546-68-9); 2.40 g of cross-linking agent - dipropylene glycol diacrylate (CAS No.: 42978-66-5, high-purity product); 41.78 g of heat-resistant reinforcing monomer - styrene (CAS No.: 100-42-5); 5.28 g of thickening agent - magnesium oxide of 325 mesh (CAS No.: 1309-48-4); 3.08 g of defoaming agent BASF Efka PB 2720; 10.99 g of mold release agent - zinc stearate of 325 mesh (CAS No.: 557-05-1‌‌).

[0094] Polyethylene glycol methyl ether methacrylate MPEG 1000MA, Hubei Shineng Chemical Technology Co., Ltd.

[0095] EWR600 fiberglass mesh cloth, Taishan Fiberglass Co., Ltd.

[0096] A preparation method of a fiberglass composite material for manufacturing special shoe tips, comprising the following steps: Step 1, the preparation method of the finished fiberglass mesh cloth is as follows: S1.1. Dissolve 0.11 mol (18.5 g) of HDI isocyanate (Wanhua HT-100) in 100 g of organic solvent DMF to obtain a mixed solution. Mix 0.1 mol (14.4 g) of hydroxypropyl methacrylate (CAS No. 27813-02-1), 0.15 g of polymerization inhibitor - hydroquinone, and 0.02 g of dibutyltin dilaurate evenly to obtain a dropping solution. Under nitrogen protection, heat the mixed solution in a water bath to 70 °C, maintain the temperature at 70 °C, and add the prepared dropping solution to the mixed solution at a dropping rate of 4 mL / min under magnetic stirring at 120 rpm. After the dropping is completed, continue stirring and reacting for 45 min, and remove the organic solvent DMF by vacuum distillation to obtain isocyanate-modified hydroxypropyl methacrylate resin; S1.2. Spray a 5 wt% aqueous solution of methacryloxy silane KH570 on the surface of EWR600 fiberglass mesh cloth, with a spraying amount of 35 g / m 2 , and then input it into an oven and dry it at 65 °C for 10 min to obtain KH570-modified fiberglass mesh cloth. The measured gram weight of the KH570-modified fiberglass mesh cloth is 601.6 g / m 2 ; S1.3. Knife-coat the isocyanate-modified hydroxypropyl methacrylate resin in S1 on the surface of the KH570-modified fiberglass mesh cloth, with a knife-coating amount of 36 g / m 2, After pre-curing and forming at 75°C for 15 minutes, the scraping material becomes gel-like, and then it is compounded with release paper, wound to obtain a finished fiberglass mesh cloth with a grammage of 637.6 g / m 2 with surface modification treatment; At the same time, prepare an impregnating resin composition: Weigh accurately 186.90 g of propyl methacrylate, 44.0 g of methoxypolyethylene glycol methacrylate MPEG 1000MA, 33.0 g of the side-chain acrylate-modified hydroxyl-terminated polysiloxane synthesized in Preparation Example 1, 33.0 g of low-shrinkage resin - polycaprolactone NPG200, 0.88 g of tetraisopropyl titanate, 41.78 g of heat-resistant reinforcing monomer - styrene, 5.28 g of thickening agent - magnesium oxide with a mesh size of 325, 3.08 g of defoaming agent BASF Efka PB2720, 10.99 g of mold release agent - zinc stearate with a mesh size of 325 into a reaction kettle, stir and degas under nitrogen protection for 45 minutes. After degassing is completed, add accurately weighed 1.10 g of benzoyl peroxide BPO and 2.40 g of cross-linking agent - dipropylene glycol diacrylate, and mix evenly to obtain the impregnating resin composition; Step 2: Divide 362.4 g of the impregnating resin composition in Step 1 into two equal parts, and evenly coat the two divided impregnating resin compositions on the surface of release paper respectively, and pre-cure at 60°C to form a gel film state to obtain a thermosetting resin composition film sheet compounded with release paper; Step 3: Compound two obtained thermosetting resin composition film sheets on the upper and lower surfaces of the finished fiberglass mesh cloth with surface modification treatment prepared in Step 1 to obtain a fiberglass prepreg with a thickness of 0.6 ± 0.005 mm. Compound release paper on the surface of the fiberglass prepreg, and place it at 40°C for curing for 36 hours; Step 4: Cut the cured fiberglass prepreg to obtain a finished fiberglass prepreg in the shape of a molding die. Stack the preformed shoe tips by the manual lamination method, place the preformed shoe tips in a hot press for hot pressing and forming treatment. The hot pressing and forming parameters are as follows: First, pressurize to 20 MPa at a rate of 1 MPa / s, hold the pressure for 60 s at a hot pressing temperature of 125°C, then pressurize to 40 MPa at a rate of 2 MPa / s, hold the pressure for 120 s at a hot pressing temperature of 155°C, demold, trim the edges, and polish to obtain a finished plastic-steel shoe tip with a wall thickness of 8.0 mm.

[0097] Example 2 is different from Example 1 in that: A preparation method of a glass fiber composite material for manufacturing a special shoe tip is as follows. The first step is the same as that in Example 1. In the second step, 362.4 g of the impregnating resin composition in the first step is evenly divided into two parts. The two evenly divided impregnating resin compositions are respectively and evenly coated on the upper and lower surfaces of the finished glass fiber grid cloth, and then release paper is laminated. It is cured at 40 °C for 36 h. In the third step, the cured glass fiber prepreg is cut into a finished glass fiber prepreg in the shape of a forming mold. The finished glass fiber prepreg is stacked into a preformed shoe tip by the manual layering method. The preformed shoe tip is placed in a hot press for hot pressing and forming treatment. The hot pressing and forming parameters are as follows: First, it is pressurized to 20 MPa at a rate of 1 MPa / s, held at a hot pressing temperature of 125 °C for 60 s, then pressurized to 40 MPa at a rate of 2 MPa / s, and held at a hot pressing temperature of 155 °C for 120 s. After demolding, trimming, and polishing, a finished plastic-steel shoe tip with a wall thickness of 8.0 mm is obtained.

[0098] Example 3 is different from Example 1 in that: In the glass fiber prepreg, methoxypolyethylene glycol methacrylate MPEG1000MA is replaced by hydroxypropyl methacrylate, and the other components remain unchanged.

[0099] Example 4 is different from Example 1 in that: In the glass fiber prepreg, 44 g of methoxypolyethylene glycol methacrylate MPEG 1000MA and 33 g of the side-chain acrylate-modified hydroxy-terminated polysiloxane synthesized in Preparation Example 1 are replaced by 77 g of hydroxypropyl methacrylate, and the other components remain unchanged.

[0100] Example 5 is different from Example 1 in that: In the glass fiber prepreg, the side-chain acrylate-modified hydroxy-terminated polysiloxane synthesized in Preparation Example 1 is replaced by the side-chain acrylate-modified hydroxy-terminated polysiloxane synthesized in Preparation Example 2.

[0101] Example 6 is different from Example 1 in that: In the glass fiber prepreg, the side-chain acrylate-modified hydroxy-terminated polysiloxane synthesized in Preparation Example 1 is replaced by the side-chain acrylate-modified hydroxy-terminated polysiloxane synthesized in Preparation Example 3.

[0102] Example 7 is different from Example 1 in that: In the glass fiber prepreg, the side-chain acrylate-modified hydroxy-terminated polysiloxane synthesized in Preparation Example 1 is replaced by the side-chain acrylate-modified hydroxy-terminated polysiloxane synthesized in Preparation Example 4.

[0103] Example 8 is different from Example 1 in that: In the glass fiber prepreg, the side-chain acrylate-modified hydroxy-terminated polysiloxane synthesized in Preparation Example 1 is replaced by side-chain acrylate-modified silicone oil IOTA 170. The side-chain acrylate-modified silicone oil IOTA 170 is provided by Anhui Aiyota Silicone Oil Co., Ltd.

[0104] The difference between Comparative Example 1 and Example 1 lies in that 186.9 g of propyl methacrylate, 44 g of methoxypolyethylene glycol methacrylate MPEG 1000MA, and 33 g of the side-chain acrylate-modified hydroxyl-terminated polysiloxane synthesized in Preparation Example 1 in the glass fiber prepreg are replaced with 263.9 g of propyl methacrylate, and the other components are the same.

[0105] The difference between Control Group A and Example 1 lies in that in Step 1 of the preparation method of the glass fiber composite material for manufacturing special shoe tips, the preparation method of the finished glass fiber grid cloth is as follows: S1.1. Spray an aqueous solution of methacryloxy silane KH570 with a concentration of 5 wt% on the surface of the EWR600 glass fiber grid cloth, and the spraying amount is 32 g / m 2 , and then put it into an oven and dry it at 65 °C for 10 min to obtain the KH570-modified glass fiber grid cloth; S1.2. Scrape the hydroxypropyl methacrylate (CAS No. 27813-02-1) prepared in S1 on the surface of the KH570-modified glass fiber grid cloth, and the scraping amount is 36 g / m 2 . After pre-curing and forming at 75 °C for 15 min, the scraping material becomes gel-like, and then it is compounded with release paper and wound up to obtain the finished glass fiber prepreg.

[0106] The difference between Control Group B and Example 1 lies in that the preparation method of the glass fiber composite material for manufacturing special shoe tips is as follows: Step 1, the preparation method of the finished glass fiber grid cloth is as follows: Spray an aqueous solution of methacryloxy silane KH570 with a concentration of 5 wt% on the surface of the EWR600 glass fiber grid cloth, and the spraying amount is 32 g / m 2 , and then put it into an oven and dry it at 65 °C for 10 min to obtain the KH570-modified glass fiber grid cloth, and no interfacial modification resin is used for modification treatment; Step 2, divide 362.4 g of the impregnating resin composition in Step 1 into two equal parts, evenly coat the two divided impregnating resin compositions on the surface of the release paper respectively, pre-cure at 60 °C to form a gel film state to obtain a thermosetting resin composition film sheet compounded with release paper, and compound the two obtained thermosetting resin composition film sheets on the upper and lower surfaces of the surface-modified finished glass fiber grid cloth prepared in Step 1 to obtain a glass fiber prepreg with a thickness of 0.6 ± 0.005 mm. Compound release paper on the surface of the glass fiber prepreg and cure it at 40 °C for 36 h; Step 3: Cut the aged fiberglass prepreg into a finished fiberglass prepreg in the shape of a forming mold. Stack the preformed shoe tips by hand lay-up method. Place the preformed shoe tips in a hot press for hot pressing and forming. The hot pressing and forming parameters are as follows: First, pressurize to 20 MPa at a rate of 1 MPa / s, hold the pressure for 60 s at a hot pressing temperature of 125°C, then pressurize to 40 MPa at a rate of 2 MPa / s, hold the pressure for 120 s at a hot pressing temperature of 155°C, demold, trim, and polish to obtain a finished plastic-steel shoe tip with a wall thickness of 8.0 mm.

[0107] Performance detection test: The safety shoe tip size is 8#.

[0108] 1. Residual height after 200J impact (mm): Measured in accordance with the requirements of European standard EN22568-2019.

[0109] 2. Residual height after 15kN impact (mm): Measured in accordance with the requirements of European standard EN22568-2019.

[0110] Table 1: Test parameter table of fiberglass composites used to manufacture special shoe tips 8# in Examples 1-8, Comparative Example 1, and Control Groups A-B Combining Examples 1-8 and Comparative Example 1 and referring to Table 1, it can be seen that the thermosetting resin composition in the thermosetting resin composition includes acrylate resin and hydroxy acrylate resin, and the prepared plastic-steel shoe tips have good compressive strength and impact toughness.

[0111] Combining Examples 1-2 and Examples 2-3 and referring to Table 1, it can be seen that the plastic-steel shoe tips prepared from the thermosetting resin composition composed of propyl methacrylate, polyethylene glycol methyl ether methacrylate, and self-made side-chain acrylate-modified hydroxy-terminated polysiloxane have excellent compressive strength and impact toughness.

[0112] Combined with Examples 1, 5 - 7 and Example 7 and in combination with Table 1, it can be seen that the compressive strength and impact toughness of the plastic - steel shoe toes prepared from the thermosetting resin composition composed of the self - made side - chain acrylate - modified hydroxyl - terminated polysiloxane in the present invention are superior to those of the plastic - steel shoe toes prepared from the thermosetting resin composition composed of the commercially available side - chain acrylate - modified silicone oil IOTA 170 in Example 8. However, from the perspective of the component composition of the thermosetting resin composition, the compressive strength and impact toughness of the plastic - steel shoe toes prepared from the thermosetting resin composition added with the self - made side - chain acrylate - modified hydroxyl - terminated polysiloxane or side - chain acrylate - modified silicone oil IOTA 170 are superior to those in Examples 3 - 4. That is, the addition of the self - made side - chain acrylate - modified hydroxyl - terminated polysiloxane or side - chain acrylate - modified silicone oil IOTA 170 has an effect of enhancing and toughening the finally prepared plastic - steel shoe toes.

[0113] The difference between Example 9 and Example 1 is that: the total addition amount of the thermosetting resin composition in the glass fiber prepreg remains unchanged, and the mass ratio of propyl methacrylate, methoxypolyethylene glycol methacrylate MPEG 1000MA, and the side - chain acrylate - modified hydroxyl - terminated polysiloxane synthesized in Preparation Example 1 is adjusted from 85:20:15 in Example 1 to 108:6:6 of propyl methacrylate, methoxypolyethylene glycol methacrylate MPEG 1000MA, and the side - chain acrylate - modified hydroxyl - terminated polysiloxane synthesized in Preparation Example 1.

[0114] The difference between Example 10 and Example 1 is that: the total addition amount of the thermosetting resin composition in the glass fiber prepreg remains unchanged, and the mass ratio of propyl methacrylate, methoxypolyethylene glycol methacrylate MPEG 1000MA, and the side - chain acrylate - modified hydroxyl - terminated polysiloxane synthesized in Preparation Example 1 is adjusted from 85:20:15 in Example 1 to 96:12:12 of propyl methacrylate, methoxypolyethylene glycol methacrylate MPEG 1000MA, and the side - chain acrylate - modified hydroxyl - terminated polysiloxane synthesized in Preparation Example 1.

[0115] The difference between Example 11 and Example 1 is that: the total addition amount of the thermosetting resin composition in the glass fiber prepreg remains unchanged, and the mass ratio of propyl methacrylate, methoxypolyethylene glycol methacrylate MPEG 1000MA, and the side - chain acrylate - modified hydroxyl - terminated polysiloxane synthesized in Preparation Example 1 is adjusted from 85:20:15 in Example 1 to 84:18:18 of propyl methacrylate, methoxypolyethylene glycol methacrylate MPEG 1000MA, and the side - chain acrylate - modified hydroxyl - terminated polysiloxane synthesized in Preparation Example 1.

[0116] Example 12 is different from Example 1 in that: the total addition amount of the thermosetting resin composition in the glass fiber prepreg remains unchanged, and the mass ratio of propyl methacrylate, methoxypolyethylene glycol methacrylate MPEG 1000MA, and the side-chain acrylate-modified hydroxyl-terminated polysiloxane synthesized in Preparation Example 1 is adjusted from 85:20:15 in Example 1 to a mass ratio of propyl methacrylate, methoxypolyethylene glycol methacrylate MPEG 1000MA, and the side-chain acrylate-modified hydroxyl-terminated polysiloxane synthesized in Preparation Example 1 of 84:24:12.

[0117] Example 13 is different from Example 1 in that: the total addition amount of the thermosetting resin composition in the glass fiber prepreg remains unchanged, and the mass ratio of propyl methacrylate, methoxypolyethylene glycol methacrylate MPEG 1000MA, and the side-chain acrylate-modified hydroxyl-terminated polysiloxane synthesized in Preparation Example 1 is adjusted from 85:20:15 in Example 1 to a mass ratio of propyl methacrylate, methoxypolyethylene glycol methacrylate MPEG 1000MA, and the side-chain acrylate-modified hydroxyl-terminated polysiloxane synthesized in Preparation Example 1 of 78:30:18.

[0118] The test control group C is different from Example 1 in that: the total addition amount of the thermosetting resin composition in the glass fiber prepreg remains unchanged, and the mass ratio of propyl methacrylate, methoxypolyethylene glycol methacrylate MPEG 1000MA, and the side-chain acrylate-modified hydroxyl-terminated polysiloxane synthesized in Preparation Example 1 is adjusted from 85:20:15 in Example 1 to a mass ratio of propyl methacrylate, methoxypolyethylene glycol methacrylate MPEG 1000MA, and the side-chain acrylate-modified hydroxyl-terminated polysiloxane synthesized in Preparation Example 1 of 60:30:30.

[0119] The test control group C also falls within the protection scope of the present invention. In order to enable readers to better understand the influence of the ratio of propyl methacrylate, methoxypolyethylene glycol methacrylate, and side-chain acrylate-modified hydroxyl-terminated polysiloxane on the impact resistance and compressive strength of the finally prepared glass fiber safety toe cap, the technical solution of the test control group C is used as a comparative test solution.

[0120] The technical solution of the control group C also meets the requirements of European standard EN22568, spiked CSA, and American standard ASTM: the glass fiber safety toe cap can provide impact protection during a 200J energy test and pressure resistance protection during a 15kN pressure test, and the minimum distance inside the toe cap is ≥21.0mm during the test.

[0121] Table 2: Test parameter table of the glass fiber composite materials used to manufacture special toe caps in Example 1, Examples 9 - 13, and control group C Combined with Example 1, Examples 9 - 13 and Control Group C and with reference to Table 2, it can be seen that the mass ratio of propyl methacrylate, methoxypolyethylene glycol methacrylate, and hydroxy - terminated polysiloxane modified with side - chain acrylate in the thermosetting resin composition affects the mechanical strength and impact resistance of the fiberglass safety toe cap. Preferably, the mass ratio of propyl methacrylate, methoxypolyethylene glycol methacrylate, and hydroxy - terminated polysiloxane modified with side - chain acrylate is (80 - 100):(5 - 30):(5 - 20), which can ensure the mechanical strength and impact resistance of the fiberglass safety toe cap, and the thermosetting resin composition in Example 1 is the preferred solution.

[0122] The difference between Example 14 and Example 1 is that the cross - linker, dipropylene glycol diacrylate, in the fiberglass prepreg resin is replaced with trimethylolpropane triacrylate (CAS No.: 15625 - 89 - 5, premium grade).

[0123] The difference between Example 15 and Example 1 is that the cross - linker, dipropylene glycol diacrylate, in the fiberglass prepreg is replaced with HDI trimer curing agent PB39009 (Guangdong Wengjiang Chemical Reagent Co., Ltd.).

[0124] The difference between Example 16 and Example 1 is that the cross - linker, dipropylene glycol diacrylate, in the fiberglass prepreg resin is replaced with pentaerythritol triacrylate (CAS No.: 3524 - 68 - 3, synthetic grade).

[0125] The difference between Example 17 and Example 1 is that 2.4 g of the cross - linker, dipropylene glycol diacrylate, in the fiberglass prepreg resin is replaced with 1.3 g of HDI trimer curing agent PB39009 and 1.1 g of trimethylolpropane triacrylate.

[0126] The difference between Comparative Example 2 and Example 1 is that 2.40 g of the cross - linker, dipropylene glycol diacrylate, is not added to the fiberglass prepreg resin, and 2.40 g of the cross - linker, dipropylene glycol diacrylate, is replaced with 110 g of propyl methacrylate in equal mass, and the other components are the same.

[0127] The difference between Comparative Example 3 and Example 1 is that the fiberglass prepreg is made from the following raw materials by mass: EWR600 fiberglass mesh fabric with a surface modification treatment of 637.60 g; 219.18 g of propyl methacrylate; 51.57 g of polyethylene glycol methyl ether methacrylate MPEG 1000MA; 38.68 g of the side-chain acrylate-modified hydroxyl-terminated polysiloxane synthesized in Preparation Example 1; 33.0 g of low-shrinkage resin - polycaprolactone NPG200; 1.10 g of benzoyl peroxide BPO; 0.88 g of tetraisopropyl titanate; 2.40 g of crosslinking agent - dipropylene glycol diacrylate; 5.28 g of thickener - magnesium oxide with a mesh size of 325; 3.08 g of defoamer BASF Efka PB 2720; 10.99 g of mold release agent - zinc stearate with a mesh size of 325. The preparation method of Comparative Example 3 is the same as that of Example 1.

[0128] Table 3: Test parameter table of fiberglass composites used to manufacture special shoe tips in Examples 1, 14 - 17 and Comparative Examples 2 - 3 Combined with Examples 1, 14 - 17 and Comparative Examples 2 - 3 and Table 3, it can be seen that the appropriate addition of at least one crosslinking agent among dipropylene glycol diacrylate, trimethylolpropane triacrylate, HDI trimer curing agent, and pentaerythritol triacrylate in the thermosetting resin composition can improve the compressive strength and impact strength of the plastic-steel safety shoe tip. Excessive addition will lead to an increase in the brittleness of the plastic-steel safety shoe tip and affect the impact toughness of the plastic-steel safety shoe tip.

[0129] Combined with Examples 1, 14 - 17 and Comparative Example 3 and Table 3, it can be seen that the addition of styrene in the thermosetting resin composition can improve the compressive strength and impact strength of the plastic-steel safety shoe tip.

[0130] The difference between Example 18 and Example 1 is that the cured finished fiberglass prepreg is laminated into a preformed shoe tip by the manual lay-up method, and the preformed shoe tip is placed in a hot press for hot pressing and forming treatment. The hot pressing and forming parameters are as follows: first pressurize to 10 MPa at a rate of 0.5 MPa / s, hold the pressure for 60 s at a hot pressing temperature of 120 °C, then pressurize to 30 MPa at a rate of 2 MPa / s, hold the pressure for 120 s at a hot pressing temperature of 160 °C, and then demold, trim, and polish to obtain the finished plastic-steel shoe tip.

[0131] The difference between Example 19 and Example 1 is as follows: The cured finished glass fiber prepreg is laminated into a preformed shoe toe by the manual lamination method. The preformed shoe toe is placed in a hot press for hot press forming treatment. The hot press forming parameters are as follows: First, pressurize to 20 MPa at a rate of 0.5 MPa / s, hold the pressure for 60 s at a hot press temperature of 130 °C, then pressurize to 40 MPa at a rate of 2.5 MPa / s, hold the pressure for 120 s at a hot press temperature of 140 °C, and then demold, trim, and polish to obtain the finished plastic-steel shoe toe.

[0132] The difference between Example 20 and Example 1 is as follows: The cured finished glass fiber prepreg is laminated into a preformed shoe toe by the manual lamination method. The preformed shoe toe is placed in a hot press for hot press forming treatment. The hot press forming parameters are as follows: First, pressurize to 20 MPa at a rate of 0.5 MPa / s, hold the pressure for 60 s at a hot press temperature of 120 °C, then pressurize to 40 MPa at a rate of 2.5 MPa / s, hold the pressure for 120 s at a hot press temperature of 160 °C, and then demold, trim, and polish to obtain the finished plastic-steel shoe toe.

[0133] The difference between Comparative Example 4 and Example 1 is as follows: The cured finished glass fiber prepreg is laminated into a preformed shoe toe by the manual lamination method. The preformed shoe toe is placed in a hot press for hot press forming treatment. The hot press forming parameters are as follows: Pressurize to 40 MPa at a rate of 2 MPa / s, hold the pressure for 120 s at a hot press temperature of 160 °C, and then demold, trim, and polish to obtain the finished plastic-steel shoe toe.

[0134] Table 4: Test parameter table of the glass fiber composite materials used to manufacture special shoe toes in Examples 1, 18 - 20 and Comparative Example 4 Combining Examples 1, 18 - 20 and Comparative Example 4 and referring to Table 4, it can be seen that the compressive strength and impact resistance of the plastic-steel safety shoe toe prepared by the asynchronous hot press forming process in the present invention are more excellent.

[0135] In summary, the plastic-steel special shoe toe prepared by the present invention is not only light in texture, meeting the lightweight design requirements of shoe products, but also has excellent compressive strength and impact resistance, and has a relatively wide range of applications. It can be applied to shoe products such as safety shoes, labor protection shoes, work shoes, and hiking shoes.

Claims

1. A glass fiber composite material for manufacturing special toe caps, characterized by: The glass fiber composite material used to make special toe caps is made by hot pressing multiple layers of glass fiber prepreg; The glass fiber prepreg is made of the following raw materials in percentage by weight: 60-65wt% of glass fiber mesh cloth, 24-28wt% of thermosetting resin composition, 3.0-4.0wt% of low shrinkage resin, 0.15-2.0wt% of initiator, 0.20-0.30wt% of cross-linking agent, 4.0-6.0wt% of heat-resistant reinforcing monomer, 0.4-0.6wt% of thickener, 0.25-0.35wt% of defoamer, and 0.8-1.2wt% of release agent; The glass fiber mesh cloth is prepared by being surface-modified with a silane coupling agent, then impregnated with an interface modification resin, and then dried and cured; the interface modification resin is an isocyanate-modified hydroxypropyl acrylate resin; The thermosetting resin composition at least includes acrylate resin and hydroxyacrylate resin.

2. The glass fiber composite material for manufacturing special toe caps according to claim 1, characterized in that: The thermosetting resin composition is composed of propyl methacrylate, polyethylene glycol methyl ether methacrylate with a number average molecular weight of 400-1000, and a hydroxyl-terminated polysiloxane modified with a side chain acrylate with a number average molecular weight of 800-2000. The mass ratio of the propyl methacrylate, the polyethylene glycol methyl ether methacrylate with a number average molecular weight of 400-1000, and the hydroxyl-terminated polysiloxane modified with a side chain acrylate with a number average molecular weight of 800-2000 is (80-100):(5-30):(5-20).

3. The glass fiber composite material for manufacturing special toe cap according to claim 2, characterized in that: The side chain acrylate modified hydroxyl-terminated polysiloxane includes γ-methacryloxypropylmethyldimethoxysilane, dimethoxymethylpropyl silane, and methylphenyldimethoxysilane; the molar ratio of the γ-methacryloxypropylmethyldimethoxysilane, dimethoxymethylpropyl silane, and methylphenyldimethoxysilane is (1-2):5:(1-2).

4. The glass fiber composite material for manufacturing special toe caps according to claim 2, characterized in that: The preparation method of the side chain acrylate modified hydroxyl-terminated polysiloxane is as follows: 10 parts by weight of γ-methacryloxypropylmethyldimethoxysilane, 0.05-0.20 parts by weight of hydroquinone, a polymerization inhibitor, and 20-30 parts by weight of an aqueous solution are uniformly mixed, an acid solution is added to adjust the pH value to 5-6.5, and an alcoholysis reaction is carried out at 40-60° C. for 15-60 minutes to obtain a silanol mixed solution A; 10 parts by weight of dimethoxymethylpropylsilane and 20-30 parts by weight of aqueous solution are uniformly mixed, acid solution is added to adjust the pH value to 5-6.5, and alcoholysis reaction is carried out at 40-60° C. for 15-60 minutes to obtain a silanol mixed solution B; 10 parts by weight of methylphenyldimethoxysilane and 20-30 parts by weight of an aqueous solution are uniformly mixed, an acid solution is added to adjust the pH value to 5-6.5, and an alcoholysis reaction is carried out at 40-60° C. for 15-60 minutes to obtain a silanol mixed solution C; Transfer the silanol mixture B to a three-necked flask, heat it to 35-45°C in a water bath, and add silanol mixture A and silanol mixture C dropwise at 80-160rpm under magnetic stirring. The dropping speed of silanol mixture A is 1-5mL / min, and the dropping speed of silanol mixture C is 1-5mL / min. After the dropping of silanol mixture A and silanol mixture C is completed, the temperature is maintained at 35-45°C for 60-90min, and then dimethoxydimethylsilane and acid solution are added to adjust the pH value to 5-6 for end-capping reaction for 5-10min. After adding alkali solution to adjust the pH value to 7, the mixture enters a water separator for dehydration treatment, and then the obtained liquid is subjected to reduced pressure fractionation to remove the hydrolyzed silane monomers that do not participate in the reaction, so as to obtain side chain acrylate-modified hydroxyl-terminated polysiloxane.

5. The glass fiber composite material for manufacturing special toe cap according to claim 1, characterized in that: The crosslinking agent is at least one of tripropylene glycol diacrylate, trimethylolpropane triacrylate, HDI trimer curing agent, and pentaerythritol triacrylate.

6. The glass fiber composite material for manufacturing special toe caps according to claim 1, characterized in that: The low shrinkage resin is polycaprolactone NPG200; the heat-resistant reinforcing monomer is at least one of styrene and diphenylethylene.

7. The glass fiber composite material for manufacturing special toe cap according to claim 1, characterized in that: The initiator is composed of at least one of benzoyl peroxide BPO, tert-butyl peroxide 2-ethylhexanoate TBPO, and azobisisobutyronitrile AIBN and at least one of tetraisopropyl titanate and dibutyltin dilaurate.

8. The glass fiber composite material for manufacturing special toe cap according to claim 1, characterized in that: The thickener is at least one of magnesium oxide, fumed silica, organic bentonite, and montmorillonite; the defoamer is BASF Efka PB 2720 defoamer or BYK 051N defoamer; and the release agent is at least one of stearate, molybdenum disulfide, talc, and mica powder.

9. A method for preparing a glass fiber composite material for manufacturing special toe caps according to any one of claims 1 to 8, characterized in that: The following steps are involved: Step 1: pre-treating and preparing the glass fiber mesh cloth; and preparing a thermosetting resin composition at the same time; Step 2: Evenly mix the thermosetting resin composition, low shrinkage resin, initiator, crosslinking agent, heat-resistant reinforcing monomer, thickener, defoamer and release agent with accurate measurement to obtain film-making slurry, evenly apply the obtained film-making slurry on the surface of release paper, and pre-cure the film-making slurry on the surface of release paper until the film-making slurry is in a gel film state, thereby obtaining a thermosetting resin composition film sheet; Step 3, compounding two sheets of the obtained thermosetting resin composition film on the upper surface and the lower surface of the glass fiber prepreg cloth to obtain the glass fiber prepreg cloth, and the glass fiber prepreg cloth is cured at 40-50° C. for 36-48 hours; Step 4, cutting the aging treated glass fiber prepreg cloth to obtain the finished glass fiber prepreg cloth in the shape of the molding mold, the finished glass fiber prepreg cloth is stacked into a preformed toe by a manual lamination method, and the finished plastic steel toe is obtained by demolding, trimming and polishing after hot pressing treatment. The hot pressing molding parameters are as follows: first pressurize to 10-20 MPa at 0.5-1MPa / s, maintain the pressure at a hot pressing temperature of 120-130°C for 60±5s, then pressurize to 30-40 MPa at 2-2.5MPa / s, and maintain the pressure at a hot pressing temperature of 140-160°C for 120±5s.

10. The method for preparing a glass fiber composite material for manufacturing a special shoe head according to claim 9, characterized in that: The pretreatment preparation method of the glass fiber mesh cloth in step 1 is as follows: first, spray a methacryloxysilane aqueous solution on the surface of the glass fiber mesh cloth, wherein the concentration of methacryloxysilane in the methacryloxysilane aqueous solution is 4-8wt%, and the spraying amount is 5-40g / m 2 Then put it into the oven for drying, the drying temperature is 50-70℃, the drying time is 5-10min, and finally the surface of the glass fiber mesh cloth modified by methacryloxysilane is coated with isocyanate modified hydroxypropyl acrylate resin, the coating amount is 5-50g / m 2 , after pre-curing and molding at 60-75℃ for 15-20min, it is compounded with release paper and rolled up to obtain the finished glass fiber mesh cloth.

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