Low-protein natural latex sponge product as well as preparation method and application thereof

Abstract

The invention discloses a low-protein natural latex sponge product as well as a preparation method and application thereof, and belongs to the technical field of preparation of natural latex sponge products. The sponge product is prepared from 85-95 parts of low-protein natural latex, 5-10 parts of methyl methacrylate latex, 1-5 parts of a filling agent, 2-3 parts of a vulcanizing agent, 1-3 parts of an accelerant, 0.5-1.5 parts of an anti-aging agent, 1-3 parts of a foaming agent, 1-2 parts of a foam stabilizer, 0.5-2 parts of a heat sensitive agent and 0.1-0.2 part of an antibacterial agent. The heat sensitive agent comprises one or more of polyvinyl methyl ether, polyether polyoxymethylene dimethyl acetal and polypropylene glycol. One or more of the polyvinyl methyl ether, the polyether polyoxymethylene dimethyl acetal and the polypropylene glycol are used as the thermosensitive forming agent for the latex sponge, so that the problem that the gelling and shaping processes are difficult to control in the production process of a natural latex sponge product is solved, the foam latex injection molding process is controllable, the forming process is rapid, and the product quality is reliable.

Description

Technical Field

[0001] The invention relates to the technical field of preparation of natural latex sponge products, in particular to a low-protein natural latex sponge product and a preparation method and application thereof. Background Art

[0002] Latex sponge is one of the important varieties of latex products. It is a low-density continuous porous rubber material prepared by mechanical or chemical foaming of latex. It has light weight, excellent cushioning and shock-absorbing performance, good elasticity, rapid recovery after deformation, and excellent properties such as creep resistance and permanent deformation resistance, as well as fatigue resistance and aging resistance. Natural latex sponge can be made into products with special purposes such as flame retardancy, shock absorption, oil resistance, and chemical resistance. It is widely used in transportation, furniture, bedding, clothing and footwear, packaging and other fields.

[0003] The preparation process of latex sponge includes latex compounding, mechanical foaming and coagulation, injection molding, forming, demoulding, vulcanization, washing and drying. The gelation process of latex foam is the destabilization process of latex. Latex needs to maintain a high stability in the early foaming process, and after reaching a high foaming multiple and forming a fine pore structure, it needs to be quickly destabilized and shaped. The gelation of latex foam usually adopts a thermal sensitization gelation method, that is, a thermosensitive agent such as zinc oxide and various ammonium salts are added to the latex to make it gel at a certain temperature. The traditional system of zinc oxide and various ammonium salts is used as a gelling agent. The time of adding the gelling agent, the speed of the foaming machine, the injection molding temperature and other processes require technicians to have considerable experience. If improperly controlled, it is easy to cause the latex foam to gel in advance before injection molding, or the latex foam collapses due to untimely gelation after injection molding, forming quality defects of sponge products. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides a low-protein natural latex sponge product and a preparation method and application thereof.

[0005] The invention provides a low-protein natural latex sponge product, comprising the following raw materials in parts by weight: 85-95 parts of low-protein natural latex, 5-10 parts of Tianjia latex, 1-5 parts of filler, 2-3 parts of vulcanizer, 1-3 parts of accelerator, 0.5-1.5 parts of antioxidant, 1-3 parts of foaming agent, 1-2 parts of foam stabilizer, 0.5-2 parts of thermosensitive agent, and 0.1-0.2 parts of antibacterial agent;

[0006] The thermosensitizer includes one or more of polyvinyl methyl ether, polyether polyoxymethylene dimethyl acetal and polypropylene glycol.

[0007] Furthermore, the protein content of the low-protein natural latex is less than 0.2wt%, and the low-protein natural latex is obtained by hydrolysis of alkaline protease. The preparation method includes the following steps: diluting the concentrated natural latex to a total solid content of 25-35wt%, then adding 2709 alkaline protease under stirring conditions, mixing evenly and performing enzymolysis at room temperature for 5-10 hours; centrifuging and concentrating the obtained latex, and then adding 0.08-0.12wt% of sodium dodecyl sulfate stabilizer to obtain the low-protein natural latex.

[0008] Furthermore, the filler includes one or more of nano pineapple leaf fiber, nano banana stem fiber, nano hemp stem fiber and white carbon black.

[0009] Furthermore, the vulcanizing agent is sulfur; and the accelerator is accelerator ZDC.

[0010] Furthermore, the antioxidant includes antioxidant 264.

[0011] Furthermore, the foaming agent includes ammonium oleate, triethanolamine oleate or potassium ricinoleate; the foam stabilizer includes quaternary ammonium soap and / or hexadecyltrimethylammonium bromide; and the antibacterial agent is ε-polylysine.

[0012] The present invention also provides a method for preparing the low-protein natural latex sponge product according to the above-mentioned method, comprising the following steps: mixing the low-protein natural latex and Tianjia latex to obtain a mixed latex, and then adding a filler, a vulcanizing agent, an accelerator, an antioxidant and an antibacterial agent to the mixed latex in sequence under stirring conditions, continuing to stir evenly and then standing to mature; after the maturation is completed, adjusting the latex temperature to 25-30°C, adding a foaming agent and a foam stabilizer, foaming, and then adding a thermosensitive agent; after stirring evenly, injecting into a mold, placing in hot steam for gelation and shaping, and demolding, vulcanizing, washing, and drying to obtain the low-protein natural latex sponge product.

[0013] Furthermore, the standing aging time is 20 to 24 hours; after the aging is completed, the latex temperature is adjusted to 25 to 30°C; the foaming process is specifically: starting foaming at a rotation speed of 250 to 300 r / min for 8 to 15 minutes, and then adjusting the stirring speed to 120 to 180 r / min to start uniform foaming for 15 to 20 minutes; the temperature of the hot steam is 80 to 100°C, and the setting time is 5 to 10 minutes; the vulcanization is steam vulcanization, the vulcanization temperature is 90 to 100°C, and the vulcanization time is 30 to 60 minutes.

[0014] Furthermore, the washing is immersion washing, and the immersion time is 20 to 30 hours; the drying method is first centrifugal dehydration and then drying, and the drying adopts circulating hot air drying, the drying temperature is 60 to 80° C., and the drying time is 2 to 10 hours.

[0015] The present invention also provides an application of the low-protein natural latex sponge product described above in preparing a latex sponge pillow, a latex sponge mattress or a latex sponge cushion.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] The invention selects polyvinyl methyl ether, polyether polyoxymethylene dimethyl acetal and polypropylene glycol as the latex sponge heat-sensitive forming agent, which has no influence on the stability and the foaming process of the latex during the foaming process, has good fluidity during injection molding, and can be quickly gelled and formed by only being placed in hot steam for heating after injection molding, has simple operation and controllable process, and will not cause serious material waste due to poor control of the gelling process during the production process of natural latex sponge products, solves the problem that the gelling and shaping processes are difficult to control during the production process of natural latex sponge products, and the produced products are of good quality.

[0018] The latex sponge preparation method provided by the invention makes the foaming latex injection molding process convenient and controllable, the molding process is stable and fast, the product quality is stable and reliable, and is suitable for large-scale promotion and application. DETAILED DESCRIPTION

[0019] Now, various exemplary embodiments of the present invention are described in detail, and this detailed description should not be considered as a limitation of the present invention, but should be understood as a more detailed description of certain aspects, characteristics and embodiments of the present invention. It should be understood that the terms described in the present invention are only for describing specific embodiments and are not used to limit the present invention.

[0020] In addition, for the numerical range in the present invention, it is understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0021] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0022] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to the skilled artisan. The present invention description and examples are exemplary only.

[0023] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0024] In the following examples, normal temperature refers to 25-30°C, the total solid content of the concentrated natural latex used is 60wt%, purchased from Guangken Rubber Group Co., Ltd.; the alkaline protease used is 2709 alkaline protease, purchased from Nanning Dongheng Huadao Biotechnology Co., Ltd. The nano pineapple leaf fiber used is homemade, and the preparation method is as follows: 1. the pineapple leaf fiber is cut into short fibers of 1-2cm and crushed into cotton-like; 2. the treated fiber is added to 80°C, 2wt% NaOH solution and mechanically stirred for 3 hours, washed with water to neutrality, added to 3wt% dilute nitric acid solution and stirred for 3 hours at 80°C; 3. the pineapple leaf fiber is rinsed with water to neutrality and dried, and then placed in 5wt% hydrochloric acid at 90°C for 1.5 hours, then washed to neutrality by centrifugation, and dried and crushed to obtain. The following description will not be repeated.

[0025] Example 1

[0026] The preparation steps of low protein natural latex sponge products are as follows:

[0027] (1) diluting the concentrated natural rubber latex with deionized water to a total solid content of 30 wt%, then adding 2709 alkaline protease under stirring, mixing evenly and performing enzymolysis at room temperature for 8 h;

[0028] (2) centrifuging and concentrating the latex treated in step (1), and then adding 0.1 wt % sodium dodecyl sulfate to obtain a low-protein natural latex with a protein content of 0.15 wt %;

[0029] (3) Weigh 90 parts of low-protein natural rubber latex and 10 parts of Tianjia latex, 5 parts of filler nano pineapple leaf fiber, 2 parts of vulcanizing agent sulfur, 2 parts of accelerator ZDC, 1 part of antioxidant 264 and 0.1 part of antibacterial agent ε-polylysine by mass; mix the low-protein natural rubber latex and Tianjia latex, add the filler, vulcanizing agent, accelerator, antioxidant and antibacterial agent to the mixed latex in sequence under stirring, mix and stir at room temperature for 1 hour, stir evenly and let stand for 24 hours;

[0030] (4) After aging, the latex temperature was adjusted to 28°C, 2 parts of a foaming agent, potassium ricinoleate, and 1.5 parts of a foam stabilizer, quaternary ammonium soap, were added, and then foaming began at a speed of 250 r / min for 10 min, and the stirring speed was adjusted to 150 r / min to start uniform foaming. After uniform foaming for 18 min, 2 parts of a heat-sensitive agent, polyvinyl methyl ether, were added, and the mixture was stirred evenly before injection molding;

[0031] (5) The foamed latex is injected into a mold, gelled and shaped in hot steam at 80°C for 10 minutes, removed from the mold, vulcanized in hot steam at 100°C for 30 minutes, soaked for 24 hours, washed and centrifuged, and dried under circulating hot air at 60°C for 4 hours to obtain a low-protein natural latex sponge product.

[0032] Example 2

[0033] The preparation steps of low protein natural latex sponge products are as follows:

[0034] (1) diluting the concentrated natural rubber latex with deionized water to a total solid content of 25 wt%, then adding 2709 alkaline protease under stirring, mixing evenly and performing enzymolysis at room temperature for 5 h;

[0035] (2) centrifuging and concentrating the natural rubber latex treated in step (1), and then adding 0.1 wt % sodium dodecyl sulfate to obtain a low-protein natural rubber latex with a protein content of 0.18 wt %;

[0036] (3) Weigh 85 parts of low-protein natural rubber latex and 8 parts of Tianjia latex, 5 parts of filler nano pineapple leaf fiber, 2.5 parts of sulfur, 3 parts of accelerator ZDC, 0.5 parts of antioxidant 264 and 0.15 parts of antibacterial agent ε-polylysine by mass; mix the low-protein natural rubber latex and Tianjia latex, add filler, vulcanizing agent, accelerator, antioxidant and antibacterial agent to the mixed latex in sequence under stirring, mix and stir at room temperature for 1 hour, stir evenly and let stand for 20 hours;

[0037] (4) After aging, the latex temperature was adjusted to 25°C, 3 parts of foaming agent ammonium oleate and 1 part of foam stabilizer hexadecyltrimethylammonium bromide were added, and then foaming was started at 300 r / min for 8 minutes, the stirring speed was adjusted to 120 r / min and uniform foaming was started for 20 minutes, and then 1 part of heat-sensitive agent polyether polyoxymethylene dimethyl acetal was added, and injection molding was started after stirring evenly;

[0038] (5) The foamed latex is injected into a mold, gelled and shaped in hot steam at 80°C for 8 minutes, demolded, vulcanized in hot steam at 90°C for 60 minutes, soaked for 30 hours, washed and centrifuged for dehydration, and dried under circulating hot air at 80°C for 2 hours to obtain a low-protein natural latex sponge product.

[0039] Example 3

[0040] The preparation steps of low protein natural latex sponge products are as follows:

[0041] (1) diluting concentrated natural rubber latex with deionized water to a total solid content of 35 wt%, then adding alkaline protease under stirring, mixing evenly, and performing enzymolysis at room temperature for 10 h;

[0042] (2) centrifuging and concentrating the latex treated in step (1), and then adding 0.1 wt % of sodium lauryl sulfate to obtain a low-protein natural latex with a protein content of 0.10 wt %;

[0043] (3) Weigh 95 parts of low-protein natural rubber latex and 5 parts of Tianjia latex, 8 parts of filler white carbon black, 3 parts of sulfur, 1 part of accelerator ZDC, 1.5 parts of antioxidant 264 and 0.2 parts of antibacterial agent ε-polylysine by mass; mix the low-protein natural rubber latex and Tianjia latex, add filler, vulcanizing agent, accelerator, antioxidant and antibacterial agent to the mixed latex in sequence under stirring, mix and stir at room temperature for 1 hour, stir evenly and let stand for 24 hours;

[0044] (4) After aging, the latex temperature is adjusted to 30°C, 1 part of a foaming agent, triethanolamine oleate, and 2 parts of a foam stabilizer, quaternary ammonium soap, are added, and then foaming is started at a speed of 280 r / min for 15 minutes, and the stirring speed is adjusted to 180 r / min to start uniform foaming for 15 minutes, and then 0.5 parts of a heat-sensitive agent, polypropylene glycol, is added, and injection molding is started after stirring evenly;

[0045] (5) The foamed latex is injected into a mold, gelled and shaped in hot steam at 100°C for 5 minutes, removed from the mold, vulcanized in hot steam at 95°C for 40 minutes, soaked for 20 hours, washed and centrifuged for dehydration, and dried under circulating hot air at 70°C for 10 hours to obtain a low-protein natural latex sponge product.

[0046] Comparative Example 1

[0047] Same as Example 1, except that the polyvinyl methyl ether in step (4) is replaced by [Zn(NH3)4]Cl2 (zinc ammine complex, obtained by reacting zinc chloride with excess ammonia water) polypropylene glycol. Other operations are the same as Example 1.

[0048] Comparative Example 2

[0049] The same as Example 1, except that step (4) is as follows: after aging, the latex temperature is adjusted to 28°C, 2 parts of a foaming agent potassium ricinoleate and 1.5 parts of a foam stabilizer quaternary ammonium soap are added, and then foaming is started at 150 r / min. After 28 minutes, 2 parts of a heat-sensitive agent polyvinyl methyl ether are added, and injection molding is started after stirring evenly. The other steps are the same as Example 1.

[0050] Effect verification

[0051] The properties of the low-protein natural latex sponge products prepared in Examples 1 to 3 and Comparative Examples 1 to 2 were tested, and the test basis and the results obtained are shown in Table 1:

[0052] Table 1 Performance test results of each group of latex sponge products

[0053]

[0054] It can be seen from Table 1 that the low-protein natural latex sponge product prepared by the method of the present invention has excellent performance and is suitable for large-scale promotion and production.

[0055] The above description is only a preferred specific implementation manner of the present invention, and the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, and they should be covered by the protection scope of the present invention.

Claims

1. A low-protein natural latex sponge product, characterized in that: The invention comprises the following raw materials in parts by weight: 85-95 parts of low-protein natural rubber latex, 5-10 parts of Tianjia rubber latex, 1-5 parts of filler, 2-3 parts of vulcanizer, 1-3 parts of accelerator, 0.5-1.5 parts of antioxidant, 1-3 parts of foaming agent, 1-2 parts of foam stabilizer, 0.5-2 parts of thermosensitive agent, and 0.1-0.2 parts of antibacterial agent; The thermosensitizer includes one or more of polyvinyl methyl ether, polyether polyoxymethylene dimethyl acetal and polypropylene glycol.

2. The low-protein natural latex sponge product according to claim 1, characterized in that: The protein content of the low-protein natural latex is less than 0.2wt%. The preparation method of the low-protein natural latex comprises the following steps: diluting the concentrated natural latex to a total solid content of 25-35wt%, adding 2709 alkaline protease under stirring conditions, performing enzymatic hydrolysis for 5-10 hours, centrifuging and concentrating the obtained latex, and then adding 0.08-0.12wt% of sodium dodecyl sulfate stabilizer to obtain the low-protein natural latex.

3. The low-protein natural latex sponge product according to claim 1, characterized in that: The filler comprises one or more of nano pineapple leaf fiber, nano banana stem fiber, nano hemp stem fiber and white carbon black.

4. The low-protein natural latex sponge product according to claim 1, characterized in that: The vulcanizing agent is sulfur; the accelerator is accelerator ZDC.

5. The low-protein natural latex sponge product according to claim 1, characterized in that The antioxidant includes antioxidant 264.

6. The low-protein natural latex sponge product according to claim 1, characterized in that: The foaming agent includes ammonium oleate, triethanolamine oleate or potassium ricinoleate; the foam stabilizer includes quaternary ammonium soap and / or hexadecyltrimethylammonium bromide; and the antibacterial agent is ε-polylysine.

7. A method for preparing a low-protein natural rubber latex sponge product according to any one of claims 1 to 6, characterized in that: The following steps are involved: The low-protein natural latex and Tianjia latex are mixed to obtain a mixed latex, and then fillers, vulcanizers, accelerators, antioxidants and antibacterial agents are added to the mixed latex in sequence under stirring conditions, and the mixture is allowed to stand for aging after continued stirring. After aging, a foaming agent and a foam stabilizer are added for foaming, and then a thermosensitive agent is added. After stirring, the mixture is injected into a mold, placed in hot steam for gelation and shaping, and then demolding, vulcanization, washing and drying are performed to obtain the low-protein natural latex sponge product.

8. The method for preparing the low-protein natural latex sponge product according to claim 7, characterized in that: The standing aging time is 20 to 24 hours; after the aging is completed, the latex temperature is also adjusted to 25 to 30°C; the foaming process is specifically: starting to foam at a rotation speed of 250 to 300 r / min for 8 to 15 minutes, then adjusting the stirring speed to 120 to 180 r / min to start uniform foaming, and uniform foaming for 15 to 20 minutes; the temperature of the hot steam is 80 to 100°C, and the setting time is 5 to 10 minutes; the vulcanization is hot steam vulcanization, the vulcanization temperature is 90 to 100°C, and the vulcanization time is 30 to 60 minutes.

9. The method for preparing the low-protein natural latex sponge product according to claim 7, characterized in that: The washing is immersion washing, and the immersion time is 20 to 30 hours; the drying method is first centrifugal dehydration and then drying, and the drying adopts circulating hot air drying, the drying temperature is 60 to 80° C., and the drying time is 2 to 10 hours.

10. Use of the low-protein natural latex sponge product according to any one of claims 1 to 6 in the preparation of a latex sponge pillow, a latex sponge mattress or a latex sponge cushion.

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