Slow-resilience silica gel for pillow inner and preparation method of slow-resilience silica gel

Abstract

The invention belongs to the technical field of high polymer materials, and particularly relates to slow-rebound silica gel for a pillow inner and a preparation method of the slow-rebound silica gel. The preparation method of the slow-rebound silica gel for the pillow inner comprises the following steps: S1, adding 90-100 parts of aminated silica gel, 30-40 parts of polyurethane, 20-30 parts of silicon dioxide, 0.4-0.6 part of sodium carbonate and 0.4-0.6 part of a surfactant into 50-60 parts of a citric acid aqueous solution, uniformly stirring, and then mixing to obtain a rubber material; and S2, crushing the rubber material, putting the crushed rubber material into a drying oven, carrying out heat treatment, carrying out melt extrusion into a mold, and carrying out cooling molding, so as to obtain the slow-rebound silica gel for the pillow inner. The silica gel material provided by the invention has a good slow rebound effect, effectively improves the tearing strength, and can be better applied to pillow inners and other products.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of high polymer materials, and particularly relates to a slow-rebound silica gel for a pillow core and a preparation method thereof. BACKGROUND

[0002] Sleep is a periodic, spontaneous and reversible resting state of higher vertebrates, which can rest, recover and restore the brain and body, and is one of the indispensable physiological functions of the human body. In recent years, with the long-time use of mobile phones and other electronic products, the continuous change of lifestyle and the increase of social pressure, the sleep quality of people has shown a downward trend, and the number of sleep disorder patients has increased. Sleep disorders not only affect people's work, study and life, but also are accompanied by varying degrees of physical and mental symptoms. Sleep disorders mainly manifest as abnormal sleep quantity and sleep onset. Many factors affect sleep quality, one of which is the pillow. The use of a pillow makes the sleep process more comfortable, but if the inner pillow core is not properly selected or used, it will not only affect the sleep quality, but also pose a hidden danger to the health of the body.

[0003] Slow-rebound silica gel (also known as memory silica gel) is a kind of organic silica foam material with viscoelasticity, which has the biocompatibility of silica gel and the pressure dispersion characteristics of slow-rebound material. When used in a pillow core, it can provide a more comfortable sleep experience for users. The specific features of slow-rebound silica gel include: (1) the slow-rebound material slowly returns to its original state after being stressed, not instantaneously, but gradually, which can better fit the human body curve; (2) the slow-rebound silica gel pillow core can uniformly disperse the head and neck pressure, relieve neck discomfort, and is particularly suitable for people with cervical problems; (3) it can adapt to various sleeping positions such as supine and lateral recumbency, and provide overall support, thereby adapting to various sleeping positions.

[0004] A slow-rebound silica gel pillow and a preparation method thereof are disclosed in a Chinese patent (publication number CN119752184A). The silica gel, modified organosilicon, nano-silicon dioxide, nano-titanium dioxide, sodium bicarbonate, sodium dodecyl sulfate, sodium carboxymethyl cellulose, dithiodibenzothiazole and acetic acid solution are stirred uniformly, then mixed and kneaded to obtain a film, which is then crushed and vulcanized, then extruded into a pillow mold to be solidified and formed into a silica gel core, and the silica gel core is then loaded into a cotton pillowcase to obtain a slow-rebound silica gel pillow. However, this patent technology lacks research on the deformation recovery time of the material, and the tear strength also has room for improvement.

[0005] Therefore, there is an urgent need for a silica gel material for a pillow core, which is modified by treating the main material silica gel and adding other functional ingredients to achieve good slow-rebound effect and effectively improve the tear strength of the material. SUMMARY

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a slow-rebound silicone for pillow cores and its preparation method. The invention uses aminated silicone, polyurethane, silica, sodium carbonate, and surfactants, along with an aqueous citric acid solution, as raw materials. These are mixed and kneaded to obtain a rubber compound. The compound is then pulverized and placed in an oven for heat treatment. It is then melt-extruded into a mold and cooled to form the slow-rebound silicone for pillow cores. Through the synergistic effect of the components, excellent slow-rebound performance is achieved, and the tear strength of the material is improved.

[0007] A first aspect of the present invention provides a method for preparing slow-rebound silicone for pillow cores, comprising the following steps: S1. Add 90-100 parts of aminated silicone, 30-40 parts of polyurethane, 20-30 parts of silica, 0.4-0.6 parts of sodium carbonate and 0.4-0.6 parts of surfactant to 50-60 parts of citric acid aqueous solution and stir evenly, then mix to obtain rubber compound; S2. After crushing the rubber material, place it in an oven for heat treatment, melt and extrude it into a mold, cool and shape it to obtain slow rebound silicone for pillow cores.

[0008] As a preferred embodiment of the present invention, the mixing conditions are: temperature of 100~110℃ and time of 10~15min.

[0009] As a preferred embodiment of the present invention, the heat treatment conditions are: temperature of 150~160℃ and time of 15~20min.

[0010] As a preferred embodiment of the present invention, the weight parts of the aminated silicone can be 90 parts, 92 parts, 94 parts, 96 parts, 98 parts, or 100 parts, etc.

[0011] As a preferred embodiment of the present invention, the polyurethane may be in the following weight proportions: 30 parts, 32 parts, 34 parts, 36 parts, 38 parts, or 40 parts, etc.

[0012] As a preferred embodiment of the present invention, the weight parts of the silicon dioxide may be 20 parts, 22 parts, 24 parts, 26 parts, 28 parts, or 30 parts, etc.

[0013] As a preferred embodiment of the present invention, the sodium carbonate may be in the form of 0.4 parts, 0.5 parts, or 0.6 parts by weight.

[0014] As a preferred embodiment of the present invention, the surfactant may be present in parts by weight of 0.4 parts, 0.5 parts, or 0.6 parts, etc.

[0015] As a preferred embodiment of the present invention, the weight parts of the citric acid aqueous solution may be 30 parts, 32 parts, 34 parts, 36 parts, 38 parts, or 40 parts, etc.

[0016] As a preferred embodiment of the present invention, the surfactant is sodium α-alkenyl sulfonate or sodium lignin sulfonate.

[0017] As a preferred embodiment of the present invention, the preparation method of the aminated silica gel is as follows: first, the silica gel is acidified to obtain acidified silica gel; then, the acidified silica gel is aminated using N-aminoethyl-γ-aminopropyltrimethoxysilane to obtain aminated silica gel.

[0018] As a preferred technical solution of the present invention, the acidification treatment step is as follows: 40-50 parts by weight of silica gel are placed in a muffle furnace at 440-460°C for activation for 5-7 hours, and then transferred to 200-240 parts by weight of a 10% hydrochloric acid solution for stirring and acidification for 10-12 hours. After washing with deionized water and drying, acidified silica gel is obtained.

[0019] As a preferred embodiment of the present invention, the amination treatment step is as follows: by weight, 40-50 parts of the acidified silica gel are added to 200-240 parts of toluene, 10-15 parts of N-aminoethyl-γ-aminopropyltrimethoxysilane are added under a nitrogen atmosphere, the mixture is stirred at 50-60°C for 20-24 hours, cooled to room temperature, filtered to obtain filter residue, washed with methanol, and dried to obtain amination silica gel.

[0020] This invention activates the surface of silicone by acidification to remove metallic impurities and organic contaminants present on the silicone surface, and then uses the hydrolysis and condensation reaction of the diaminosilane coupling agent N-aminoethyl-γ-aminopropyltrimethoxysilane to graft amino groups onto the silicone surface, thereby obtaining amino silicone.

[0021] As a preferred embodiment of the present invention, the polyurethane is sulfonated.

[0022] As a preferred technical solution of the present invention, the preparation steps of the sulfonated polyurethane are as follows: by weight, 20-30 parts of sulfonate polyester polyol and 20-30 parts of polytetrahydrofuran are mixed and heated to 110-120°C for vacuum dehydration for 100-120 min, then cooled to 80-90°C and 1.8-2.4 parts of 1,4-butanediol, 15-25 parts of isophorone diisocyanate and 0.4-0.6 parts of dibutyltin dilaurate are added and stirred for 2-4 h, then cooled to 55-65°C and 2-4 parts of triethylamine are added and stirred for 8-10 min, vacuum distilled, dried and pulverized to obtain sulfonated polyurethane.

[0023] As a preferred embodiment of the present invention, the sulfonate polyester polyol is Beijing Baiyuan BY-3305B, with a molecular weight of 2000 g / mol, a hydroxyl value of 50~60 mgKOH / g, an acid value of <1.5 mgKOH / g, and a moisture content of <0.1%.

[0024] This invention uses sulfonate polyester polyol as polyester polyol, polytetrahydrofuran as polyether polyol, and 1,4-butanediol as small molecule chain extender, and carries out polymerization reaction with catalysts dibutyltin dilaurate, isophorone diisocyanate and triethylamine to prepare anionic sulfonate polyurethane.

[0025] As a preferred embodiment of the present invention, the silicon dioxide is dendritic molecular grafted silicon dioxide.

[0026] As a preferred embodiment of the present invention, the method for preparing the dendritic molecule-grafted silica is as follows: methyl 3,4,5-trihydroxybenzoate, anhydrous potassium carbonate, 1,4-dioxane, benzyl chloride, and tert-butylamine hydroiodate are mixed and reacted at elevated temperature to obtain intermediate A; intermediate A and hydrazine hydrate are dissolved in a solvent and stirred under reflux to obtain intermediate B; intermediate B, triethylamine, and methyl acrylate are mixed and reacted under stirring to obtain dendritic molecules; the dendritic molecules are used to graft carboxylated silica to obtain dendritic molecule-grafted silica.

[0027] As a preferred technical solution of the present invention, the preparation steps of intermediate A are as follows: by weight, 18-20 parts of methyl 3,4,5-trihydroxybenzoate, 48-50 parts of anhydrous potassium carbonate and 250-260 parts of 1,4-dioxane are mixed, then 66-70 parts of benzyl chloride and 2.6-2.8 parts of tert-butylamine hydroiodate are added, the mixture is heated to 105-115°C and reacted for 20-24 hours, then rotary evaporated and recrystallized to obtain intermediate A.

[0028] As a preferred technical solution of the present invention, the preparation steps of intermediate B are as follows: 60-70 parts by weight of methanol and 30-40 parts by weight of tetrahydrofuran are mixed, and then 8-10 parts by weight of intermediate A and 40-44 parts by weight of hydrazine hydrate are added. The mixture is stirred and refluxed at 70-80°C for 10-12 hours. After the reaction is completed, the mixture is cooled to room temperature and rotary evaporated to obtain intermediate B.

[0029] As a preferred embodiment of the present invention, the preparation steps of the dendritic molecules are as follows: by weight, 100-120 parts of methanol and 100-120 parts of dichloromethane are mixed, then 6-8 parts of the intermediate B are added, and under ice bath conditions, 8-10 parts of triethylamine and 100-120 parts of methyl acrylate are added and stirred for 48-50 hours. The mixture is then rotary evaporated, washed with diethyl ether, and dried to obtain a solid. 6-8 parts of the solid are redissolved in a mixture of 100-120 parts of methanol and 100-120 parts of dichloromethane, and under ice bath conditions, 80-90 parts of ethylenediamine are added and stirred for 48-50 hours. After the reaction is completed, 90-100 parts of dichloromethane are added for dissolution, and the organic layer is rotary evaporated to obtain the dendritic molecules.

[0030] As a preferred embodiment of the present invention, the grafting reaction steps are as follows: by weight, 0.8 to 1.2 parts of dendritic molecules are added to 280 to 300 parts of dichloromethane and fully dissolved, then 4 to 6 parts of carboxylated silica are added and ultrasonically dispersed for 20 to 30 minutes, 0.2 to 0.4 parts of N,N'-dicyclohexylcarboimide and 0.2 to 0.4 parts of 4-dimethylaminopyridine are added under ice bath conditions, and the mixture is stirred at room temperature for 40 to 48 hours, filtered, washed with dichloromethane, and dried to obtain dendritic molecule grafted silica.

[0031] This invention involves mixing methyl 3,4,5-trihydroxybenzoate, anhydrous potassium carbonate, 1,4-dioxane, benzyl chloride, and tert-butylamine hydroiodate and reacting them at elevated temperatures to obtain intermediate A. This intermediate A is then dissolved in hydrazine hydrate in a solvent and stirred under reflux to obtain intermediate B. Intermediate B, triethylamine, and methyl acrylate are then mixed and reacted to obtain dendritic molecules. Finally, an N,N'-dicyclohexylcarboimide / 4-dimethylaminopyridine catalytic system is used to covalently graft the dendritic molecules onto carboxylated silica, resulting in dendritic molecule-grafted silica.

[0032] A second aspect of the present invention provides a slow-rebound silicone pillow core prepared by the preparation method described in the first aspect.

[0033] Compared with the prior art, the present invention has the following beneficial effects: (1) The sulfonated polyurethane of the present invention forms an ionic cross-linking network by electrostatic attraction between sulfonic acid groups and amino silica and the amino groups of dendritic molecules grafted onto silica. At the same time, the polar groups in the three materials can form a hydrogen bond network. The tear strength of the material is significantly improved through multiple networks. In addition, the reversible breaking and recombination characteristics of ionic bonds combined with the dynamic reversibility of hydrogen bonds enable the material to obtain slow rebound characteristics.

[0034] (2) The amino-modified silicone of the present invention can form additional hydrogen bond interactions in the silicone network through amino groups, thereby increasing the resistance to chain segment movement and delaying stress relaxation, making the material recover its original shape more slowly after being compressed, increasing the deformation recovery time to achieve slow rebound; at the same time, the hydrogen bond network formed by the amino group acts as a reversible and dynamic temporary cross-linking point, working together with the original silicone network to effectively improve the tear strength of the material.

[0035] (3) The sulfonic acid groups contained in the sulfonated polyurethane molecular chain of the present invention have strong polarity and can form multiple hydrogen bonds and ionic bonds with the silicone molecular chain and the polyurethane molecular chain to construct a relaxed cross-linking network. When subjected to pressure, the cross-linking network will slowly untangle and release stress. After the pressure is removed, the molecular chain will recombine through hydrogen bonds and ionic bonds and slowly return to the initial form, thus exhibiting excellent slow rebound characteristics. In addition, the rigid segments of the sulfonate polyester polyol and the flexible segments of polytetrahydrofuran form a rigid-flexible synergistic structure to prevent the molecular chain from slipping rapidly under stress, thereby improving the tear resistance of the material.

[0036] (4) In the present invention, the dendritic molecules in the grafted silica have a three-dimensional branched structure, forming multiple physical entanglement points and reversible hydrogen bond networks in the silica network. When subjected to compression deformation, these dynamic non-covalent interactions can be reversibly broken and recombined, dissipating mechanical energy and prolonging the rebound time, thereby achieving a slow rebound effect. At the same time, the grafted silica, as a nano toughening agent, is uniformly dispersed in the matrix to avoid stress concentration, and absorbs tearing energy through crack deflection and local plastic deformation, significantly improving tear resistance. Detailed Implementation

[0037] To facilitate understanding of the present invention, the following embodiments are provided. Those skilled in the art should understand that these embodiments are merely illustrative and should not be construed as limiting the scope of the invention.

[0038] The sources of some components in the examples and comparative examples are as follows: Commercially available silicone, product number S141265, purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. Commercially available polyurethane, part number 1180A10, purchased from BASF; Carboxylated silica, product number XFF31-2, was purchased from Jiangsu Xianfeng Nanomaterials Technology Co., Ltd. Sodium carbonate, CAS No. 497-19-8, was purchased from Sinopharm Chemical Reagent Co., Ltd. Sodium α-alkenylsulfonate, CAS No. 68439-57-6, was purchased from Shanghai Maclean Biochemical Technology Co., Ltd. Sodium lignosulfonate, CAS No. 8061-51-6, was purchased from Shanghai Maclean Biochemical Technology Co., Ltd. Citric acid, CAS No. 77-92-9, was purchased from Shanghai Maclean Biochemical Technology Co., Ltd. N-aminoethyl-γ-aminopropyltrimethoxysilane, CAS No. 1760-24-3, was purchased from Shanghai Maclean Biochemical Technology Co., Ltd. Sulfonate polyester polyol, brand name BY-3305B, molecular weight 2000 g / mol, hydroxyl value 50~60 mgKOH / g, acid value <1.5 mgKOH / g, moisture content <0.1%, purchased from Beijing Baiyuan Chemical Co., Ltd. Polytetrahydrofuran, product number P141386, was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. Isophorone diisocyanate, product number I109582, was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. 1,4-Butanediol, CAS No. 110-63-4, purchased from Shanghai Maclean Biochemical Technology Co., Ltd. Dibutyltin dilaurate, CAS No. 77-58-7, was purchased from Shanghai Maclean Biochemical Technology Co., Ltd. Methyl 3,4,5-trihydroxybenzoate, CAS No. 99-24-1, purchased from Sinopharm Chemical Reagent Co., Ltd. Anhydrous potassium carbonate, CAS No. 584-08-7, purchased from Sinopharm Chemical Reagent Co., Ltd. 1,4-Dioxane, CAS No. 123-91-1, purchased from Shanghai Maclean Biochemical Technology Co., Ltd. Benzyl chloride, CAS No. 100-44-7, was purchased from Shanghai Maclean Biochemical Technology Co., Ltd. tert-butylamine hydroiodide, CAS No. 39557-45-4, was purchased from Shanghai Maclean Biochemical Technology Co., Ltd. Hydrazine hydrate, CAS No. 10217-52-4, was purchased from Sinopharm Chemical Reagent Co., Ltd. Triethylamine, CAS No. 121-44-8, was purchased from Sinopharm Chemical Reagent Co., Ltd. Methyl acrylate, CAS No. 96-33-3, was purchased from Shanghai Maclean Biochemical Technology Co., Ltd. Carboxylated silica, product number XFF31-2, was purchased from Jiangsu Xianfeng Nanomaterials Technology Co., Ltd. N,N'-Dicyclohexylcarboimide (DCC), product number D106074, was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. 4-Dimethylaminopyridine, CAS No. 1122-58-3, was purchased from Shanghai Maclean Biochemical Technology Co., Ltd.

[0039] Example 1 This embodiment provides a method for preparing slow-rebound silicone for pillow cores, including the following steps: S1. Add 100 parts of aminated silicone, 40 parts of sulfonated polyurethane, 30 parts of dendritic grafted silica, 0.6 parts of sodium carbonate and 0.6 parts of surfactant α-alkenyl sulfonate to 60 parts of citric acid aqueous solution and stir evenly. Then, knead (temperature 110℃, time 10min) to obtain the rubber compound. S2. After crushing the rubber material, place it in an oven for heat treatment (temperature 160℃, time 20min), melt and extrude it into a mold, cool and shape it to obtain slow rebound silicone for pillow cores.

[0040] Preparation of the aminated silica gel: 50 parts by weight of silica gel were activated in a muffle furnace at 460°C for 5 hours, then transferred to 240 parts by weight of a 10% hydrochloric acid solution and stirred for 12 hours. After washing with deionized water and drying, acidified silica gel was obtained. 50 parts of the acidified silica gel were added to 240 parts of toluene, and 15 parts of N-aminoethyl-γ-aminopropyltrimethoxysilane were added under a nitrogen atmosphere. The mixture was stirred at 60°C for 20 hours, cooled to room temperature, filtered to obtain filter residue, washed with methanol, and dried to obtain aminated silica gel.

[0041] Preparation of the sulfonated polyurethane: By weight, 30 parts of sulfonate polyester polyol and 30 parts of polytetrahydrofuran are mixed and heated to 120°C for vacuum dehydration for 100 min. Then, the temperature is lowered to 90°C and 2.4 parts of 1,4-butanediol, 25 parts of isophorone diisocyanate and 0.6 parts of dibutyltin dilaurate are added and stirred for 4 h. Then, the temperature is lowered to 65°C and 4 parts of triethylamine are added and stirred for 8 min. The mixture is then vacuum distilled, dried, and pulverized to obtain the sulfonated polyurethane.

[0042] Preparation of the dendritic grafted silica: First, by weight, 20 parts of methyl 3,4,5-trihydroxybenzoate, 50 parts of anhydrous potassium carbonate, and 260 parts of 1,4-dioxane are mixed, then 70 parts of benzyl chloride and 2.8 parts of tert-butylamine hydroiodate are added. The mixture is heated to 115°C and reacted for 24 hours. After rotary evaporation and recrystallization, intermediate A is obtained. Then, 70 parts of methanol and 30 parts of tetrahydrofuran are mixed, followed by the addition of 10 parts of intermediate A and 44 parts of hydrazine hydrate. The mixture is stirred and refluxed at 80°C for 10 hours. After the reaction is complete, the mixture is cooled to room temperature and rotary evaporated to obtain intermediate B. Finally, 120 parts of methanol and 120 parts of dichloromethane are mixed, followed by the addition of 8 parts of intermediate B. Then, under ice bath conditions, 10 parts of triethylamine and 120 parts of... Methyl acrylate was stirred for 50 h, rotary evaporated, washed with diethyl ether, and dried to obtain a solid. Eight parts of the solid were redissolved in a mixture of 120 parts methanol and 20 parts dichloromethane. 90 parts ethylenediamine were added under ice bath conditions and stirred for 50 h. After the reaction was complete, 100 parts dichloromethane were added for dissolution. The organic layer was taken and rotary evaporated to obtain dendritic molecules. 1.2 parts of the dendritic molecules were added to 300 parts dichloromethane and dissolved completely. Then, 6 parts carboxylated silica were added and ultrasonically dispersed for 30 min. Under ice bath conditions, 0.4 parts N,N'-dicyclohexylcarboimide and 0.4 parts 4-dimethylaminopyridine were added. The mixture was stirred at room temperature for 48 h, filtered, washed with dichloromethane, and dried to obtain dendritic molecules grafted with silica.

[0043] Example 2 This embodiment provides a method for preparing slow-rebound silicone for pillow cores, including the following steps: S1. Add 90 parts of aminated silicone, 30 parts of sulfonated polyurethane, 20 parts of dendritic grafted silica, 0.4 parts of sodium carbonate and 0.4 parts of surfactant sodium lignosulfonate to 50 parts of citric acid aqueous solution and stir evenly. Then, knead (temperature 100℃, time 15min) to obtain the rubber compound. S2. After crushing the rubber material, place it in an oven for heat treatment (temperature 150℃, time 20min), melt and extrude it into a mold, cool and shape it to obtain slow rebound silicone for pillow cores.

[0044] Preparation of the aminated silica gel: 40 parts by weight of silica gel were activated in a muffle furnace at 440°C for 7 hours, then transferred to 200 parts by weight of a 10% hydrochloric acid solution and stirred for 10 hours. After washing with deionized water and drying, acidified silica gel was obtained. 40 parts of the acidified silica gel were added to 200 parts of toluene, and 10 parts of N-aminoethyl-γ-aminopropyltrimethoxysilane were added under a nitrogen atmosphere. The mixture was stirred at 50°C for 24 hours, cooled to room temperature, filtered to obtain filter residue, washed with methanol, and dried to obtain aminated silica gel.

[0045] Preparation of the sulfonated polyurethane: By weight, 20 parts of sulfonate polyester polyol and 20 parts of polytetrahydrofuran are mixed and heated to 110°C for vacuum dehydration for 120 min. Then, the mixture is cooled to 80°C and 1.8 parts of 1,4-butanediol, 15 parts of isophorone diisocyanate and 0.4 parts of dibutyltin dilaurate are added and stirred for 2 h. The mixture is then cooled to 55°C and 2 parts of triethylamine are added and stirred for 10 min. The mixture is then vacuum distilled, dried, and pulverized to obtain the sulfonated polyurethane.

[0046] Preparation of the dendritic grafted silica: First, by weight, 18 parts of methyl 3,4,5-trihydroxybenzoate, 48 parts of anhydrous potassium carbonate, and 250 parts of 1,4-dioxane are mixed, then 66 parts of benzyl chloride and 2.6 parts of tert-butylamine hydroiodate are added. The mixture is heated to 105°C and reacted for 24 hours. After rotary evaporation and recrystallization, intermediate A is obtained. Next, 60 parts of methanol and 40 parts of tetrahydrofuran are mixed, then 8 parts of intermediate A and 40 parts of hydrazine hydrate are added. The mixture is stirred and refluxed at 70°C for 12 hours. After the reaction is complete, it is cooled to room temperature and rotary evaporated to obtain intermediate B. Finally, 100 parts of methanol and 100 parts of dichloromethane are mixed, then 6 parts of intermediate B are added. Under ice bath conditions, 8 parts of triethylamine and 100 parts of propane are added. Methyl acrylate was stirred for 48 h, rotary evaporated, washed with diethyl ether, and dried to obtain a solid. Six parts of the solid were redissolved in a mixture of 100 parts methanol and 100 parts dichloromethane. 80 parts ethylenediamine were added under ice bath conditions and stirred for 48 h. After the reaction was complete, 90 parts dichloromethane were added for dissolution. The organic layer was taken and rotary evaporated to obtain dendritic molecules. 0.8 parts of the dendritic molecules were added to 280 parts dichloromethane and dissolved completely. Then, 4 parts carboxylated silica were added and ultrasonically dispersed for 20 min. 0.2 parts N,N'-dicyclohexylcarboimide and 0.2 parts 4-dimethylaminopyridine were added under ice bath conditions. The mixture was stirred at room temperature for 40 h, filtered, washed with dichloromethane, and dried to obtain dendritic molecules grafted with silica.

[0047] Example 3 This embodiment provides a method for preparing slow-rebound silicone for pillow cores, including the following steps: S1. Add 95 parts of amino-modified silicone, 35 parts of sulfonated polyurethane, 25 parts of dendritic grafted silica, 0.5 parts of sodium carbonate and 0.5 parts of surfactant α-alkenyl sulfonate to 55 parts of citric acid aqueous solution and stir evenly. Then, knead (temperature 105℃, time 13min) to obtain the rubber compound. S2. After crushing the rubber material, place it in an oven for heat treatment (temperature 155℃, time 18min), melt and extrude it into a mold, cool and shape it to obtain slow rebound silicone for pillow cores.

[0048] Preparation of the aminated silica gel: 45 parts by weight of silica gel were activated in a muffle furnace at 450°C for 6 hours, then transferred to 220 parts by weight of a 10% hydrochloric acid solution and stirred for 11 hours. After washing with deionized water and drying, acidified silica gel was obtained. 45 parts of the acidified silica gel were added to 220 parts of toluene, and 12 parts of N-aminoethyl-γ-aminopropyltrimethoxysilane were added under a nitrogen atmosphere. The mixture was stirred at 55°C for 22 hours, cooled to room temperature, filtered to obtain filter residue, washed with methanol, and dried to obtain aminated silica gel.

[0049] Preparation of the sulfonated polyurethane: By weight, 25 parts of sulfonate polyester polyol and 25 parts of polytetrahydrofuran are mixed and heated to 115°C for vacuum dehydration for 110 min. Then, the mixture is cooled to 85°C and 2.2 parts of 1,4-butanediol, 20 parts of isophorone diisocyanate and 0.5 parts of dibutyltin dilaurate are added and stirred for 3 h. The mixture is then cooled to 58°C and 3 parts of triethylamine are added and stirred for 9 min. The mixture is then vacuum distilled, dried, and pulverized to obtain the sulfonated polyurethane.

[0050] Preparation of the dendritic grafted silica: First, by weight, 19 parts of methyl 3,4,5-trihydroxybenzoate, 49 parts of anhydrous potassium carbonate, and 255 parts of 1,4-dioxane are mixed, then 68 parts of benzyl chloride and 2.7 parts of tert-butylamine hydroiodate are added. The mixture is heated to 108°C and reacted for 22 hours. After rotary evaporation and recrystallization, intermediate A is obtained. Next, 65 parts of methanol and 35 parts of tetrahydrofuran are mixed, then 9 parts of intermediate A and 42 parts of hydrazine hydrate are added. The mixture is stirred and refluxed at 75°C for 11 hours. After the reaction is complete, it is cooled to room temperature and rotary evaporated to obtain intermediate B. Finally, 110 parts of methanol and 110 parts of dichloromethane are mixed, then 7 parts of intermediate B are added. Under ice bath conditions, 9 parts of triethylamine and 110 parts of propane are added. Methyl acrylate was stirred for 49 h, rotary evaporated, washed with diethyl ether, and dried to obtain a solid. Seven parts of the solid were redissolved in a mixture of 110 parts methanol and 110 parts dichloromethane. 85 parts ethylenediamine were added under ice bath conditions and stirred for 49 h. After the reaction was completed, 95 parts dichloromethane were added for dissolution. The organic layer was taken and rotary evaporated to obtain dendritic molecules. 0.9 parts of the dendritic molecules were added to 290 parts dichloromethane and dissolved completely. Then, 5 parts carboxylated silica were added and ultrasonically dispersed for 25 min. 0.3 parts N,N'-dicyclohexylcarboimide and 0.3 parts 4-dimethylaminopyridine were added under ice bath conditions. The mixture was stirred at room temperature for 44 h, filtered, washed with dichloromethane, and dried to obtain dendritic molecules grafted with silica.

[0051] Comparative Example 1 The difference between this comparative example and Example 1 is that commercially available silicone (part number S141265) was used instead of amino silicone.

[0052] Comparative Example 2 The difference between this comparative example and Example 1 is that commercially available polyurethane (product number S141265) was used instead of sulfonated polyurethane.

[0053] Comparative Example 3 The difference between this comparative example and Example 1 is that carboxylated silica (item number XFF31-2) is used instead of dendritic grafted silica.

[0054] The performance of the above embodiments and comparative examples was tested using the following methods: (1) Deformation recovery time test: The test shall be conducted in accordance with the requirements of GB / T 26392-2011 Determination of recovery time of slow rebound foam.

[0055] (2) Air permeability test: The test shall be conducted in accordance with the requirements of GB / T 5453-2025 Determination of air permeability of textile fabrics.

[0056] (3) Tear strength test: The test shall be conducted in accordance with the requirements of GB / T 10808-2006 Determination of tear strength of porous polymer elastic materials.

[0057] The performance test data above are shown in Table 1.

[0058] Table 1 Performance Test Results As can be seen from the above, the present invention uses aminated silicone, polyurethane, silica, sodium carbonate, and surfactants, along with citric acid aqueous solution, as raw materials. The mixture is stirred, mixed, and kneaded to obtain a rubber compound. The rubber compound is then pulverized and placed in an oven for heat treatment. It is then melted, extruded into a mold, and cooled to form a slow-rebound silicone for pillow cores (Examples 1 to 3), which has the best overall performance.

[0059] Compared to Example 1, commercially available silicone (product number S141265) was used instead of amino silicone. The lack of amino groups in the silicone resulted in a shorter deformation recovery time and lower tear strength (Comparative Example 1). Compared to Example 1, commercially available polyurethane (product number S141265) was used instead of sulfonated polyurethane. The lack of sulfonic acid groups in the polyurethane resulted in a shorter deformation recovery time and lower tear strength (Comparative Example 2). Compared to Example 1, carboxylated silica (product number XFF31-2) was used instead of dendritic grafted silica. The lack of dendritic molecules resulted in a shorter deformation recovery time and lower tear strength (Comparative Example 3).

Claims

1. A method for preparing slow-rebound silicone for pillow cores, characterized in that, Includes the following steps: S1. Add 90-100 parts of aminated silicone, 30-40 parts of polyurethane, 20-30 parts of silica, 0.4-0.6 parts of sodium carbonate and 0.4-0.6 parts of surfactant to 50-60 parts of citric acid aqueous solution and stir evenly, then mix to obtain rubber compound; S2. After crushing the rubber material, place it in an oven for heat treatment, melt and extrude it into a mold, cool and shape it to obtain slow rebound silicone for pillow cores; The preparation method of the aminated silica gel is as follows: first, the silica gel is acidified to obtain acidified silica gel; then, the acidified silica gel is aminated using N-aminoethyl-γ-aminopropyltrimethoxysilane to obtain aminated silica gel.

2. The method for preparing slow-rebound silicone for pillow cores according to claim 1, characterized in that, The acidification process is as follows: 40-50 parts by weight of silica gel are placed in a muffle furnace at 440-460°C for 5-7 hours to activate it, then transferred to 200-240 parts by weight of a 10% hydrochloric acid solution and stirred for 10-12 hours to acidify. The silica gel is then washed with deionized water and dried to obtain acidified silica gel.

3. The method for preparing slow-rebound silicone for pillow cores according to claim 1, characterized in that, The amination treatment steps are as follows: by weight, 40-50 parts of the acidified silica gel are added to 200-240 parts of toluene, 10-15 parts of N-aminoethyl-γ-aminopropyltrimethoxysilane are added under a nitrogen atmosphere, the mixture is stirred at 50-60°C for 20-24 hours, cooled to room temperature, filtered to obtain filter residue, washed with methanol, and dried to obtain amination silica gel.

4. The method for preparing slow-rebound silicone for pillow cores according to claim 1, characterized in that, The aforementioned is sulfonated polyurethane; The preparation steps of the sulfonated polyurethane are as follows: by weight, 20-30 parts of sulfonate polyester polyol and 20-30 parts of polytetrahydrofuran are mixed and heated to 110-120℃ for vacuum dehydration for 100-120 min, then cooled to 80-90℃ and 1.8-2.4 parts of 1,4-butanediol, 15-25 parts of isophorone diisocyanate and 0.4-0.6 parts of dibutyltin dilaurate are added and stirred for 2-4 h, then cooled to 55-65℃ and 2-4 parts of triethylamine are added and stirred for 8-10 min, vacuum distilled, dried and pulverized to obtain sulfonated polyurethane.

5. The method for preparing slow-rebound silicone for pillow cores according to claim 1, characterized in that, The silica is dendritic molecular grafted silica; The method for preparing dendritic molecular grafted silica is as follows: methyl 3,4,5-trihydroxybenzoate, anhydrous potassium carbonate, 1,4-dioxane, benzyl chloride, and tert-butylamine hydroiodate are mixed and reacted at elevated temperature to obtain intermediate A; intermediate A and hydrazine hydrate are dissolved in a solvent and stirred under reflux to obtain intermediate B; intermediate B, triethylamine, and methyl acrylate are mixed and reacted under stirring to obtain dendritic molecules; the dendritic molecules are used to graft carboxylated silica to obtain dendritic molecular grafted silica.

6. The method for preparing slow-rebound silicone for pillow cores according to claim 5, characterized in that, The preparation steps of intermediate A are as follows: by weight, 18-20 parts of methyl 3,4,5-trihydroxybenzoate, 48-50 parts of anhydrous potassium carbonate and 250-260 parts of 1,4-dioxane are mixed, then 66-70 parts of benzyl chloride and 2.6-2.8 parts of tert-butylamine hydroiodate are added, the mixture is heated to 105-115℃ and reacted for 20-24 hours, then rotary evaporated and recrystallized to obtain intermediate A.

7. The method for preparing slow-rebound silicone for pillow cores according to claim 5, characterized in that, The preparation steps of intermediate B are as follows: 60-70 parts by weight of methanol and 30-40 parts by weight of tetrahydrofuran are mixed, and then 8-10 parts by weight of intermediate A and 40-44 parts by weight of hydrazine hydrate are added. The mixture is stirred and refluxed at 70-80°C for 10-12 hours. After the reaction is completed, the mixture is cooled to room temperature and rotary evaporated to obtain intermediate B.

8. The method for preparing slow-rebound silicone for pillow cores according to claim 5, characterized in that, The preparation steps of the dendritic molecules are as follows: by weight, 100-120 parts of methanol and 100-120 parts of dichloromethane are mixed, then 6-8 parts of the intermediate B are added, and under ice bath conditions, 8-10 parts of triethylamine and 100-120 parts of methyl acrylate are added and stirred for 48-50 hours. The mixture is then rotary evaporated, washed with diethyl ether, and dried to obtain a solid. 6-8 parts of the solid are redissolved in a mixture of 100-120 parts of methanol and 100-120 parts of dichloromethane, and under ice bath conditions, 80-90 parts of ethylenediamine are added and stirred for 48-50 hours. After the reaction is completed, 90-100 parts of dichloromethane are added for dissolution, and the organic layer is rotary evaporated to obtain the dendritic molecules.

9. The method for preparing slow-rebound silicone for pillow cores according to claim 5, characterized in that, The grafting reaction is performed as follows: 0.8-1.2 parts by weight of dendritic molecules are added to 280-300 parts of dichloromethane and dissolved completely. Then, 4-6 parts of carboxylated silica are added and ultrasonically dispersed for 20-30 minutes. Under ice bath conditions, 0.2-0.4 parts of N,N'-dicyclohexylcarboimide and 0.2-0.4 parts of 4-dimethylaminopyridine are added. The mixture is stirred at room temperature for 40-48 hours, filtered, washed with dichloromethane, and dried to obtain dendritic molecule grafted silica.

10. A slow-rebound silicone for pillow cores, characterized in that, It is prepared by the preparation method according to any one of claims 1 to 9.

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