A production process of natural rubber sponge with high rubber content

Abstract

This invention provides a production process for natural latex sponges with high latex content, comprising the following steps: (1) raw material preparation and pre-vulcanization; (2) adding the pre-vulcanized latex, zinc oxide, and curing agent dispersion obtained above together into a foaming device for foaming; (3) vulcanization process; (4) washing, dehydration, and drying of the finished product. This invention's production process for natural latex sponges with high latex content allows sulfur to be evenly dispersed in the natural latex, and then, through ultrasonic waves, the sulfur can fully react with the latex, effectively shortening the latex pre-vulcanization time and increasing the foaming ratio. This not only significantly improves production efficiency and maintains the various properties of latex products, but also reduces the amount of sulfur used, and produces natural latex products with a higher latex content.

Description

Technical Field

[0001] This invention relates to the field of natural latex sponge products, and more particularly to a production process for natural latex sponges with high latex content. Technical Background

[0002] In the production and processing, the latex sponge produced by the Dunlop process involves mixing and maturing all raw materials except for the activator zinc oxide and the gelling agent sodium fluorosilicate in a mixing tank according to the formula. The matured latex is then transported through pipelines to a foaming machine for foaming, steam vulcanization, and molding. After that, it is washed, cooled, punched, and cut into shape.

[0003] Traditional vulcanization processes suffer from numerous drawbacks. Firstly, sulfur sedimentation leads to inadequate pre-vulcanization, resulting in excessive sulfur usage. Secondly, the slow sulfur dissolution process significantly reduces production efficiency. With rising living standards, consumers are increasingly focused on high-quality home furnishing products, particularly the natural latex content in latex products. Reducing sulfur usage and increasing the latex content in latex foam products are pressing issues that current production processes must address. Summary of the Invention

[0004] This invention patent addresses the above problems by providing a production process for natural latex sponges with high latex content, effectively avoiding the excessive addition of sulfur due to insufficient sulfur reaction during the pre-vulcanization process of natural latex before foaming.

[0005] The technical solution of this invention is: a production process for natural latex sponge with high latex content, comprising the following steps: (1) Raw material preparation and dispersion: After the raw materials are prepared and stirred evenly according to the formula, they are stirred at 26-30 degrees Celsius for 2-3 hours to carry out preliminary stirring and dispersion; The raw materials comprise the following components in parts by weight: natural latex: 100 parts; sulfur emulsion: 3-4 parts; potassium oleate solution: 2-5 parts; potassium castor oil solution: 0.5-2 parts; potassium pyrophosphate: 0.1-5 parts; (2) Ultrasonic pre-vulcanization process: The dispersed mixed latex liquid is introduced into a tank container that is ultrasonically vibrated and dispersed, and ultrasonic vibration vulcanization is continued at 28-30 degrees Celsius for 1-2 hours. (3) The prepared pre-vulcanized latex, zinc oxide and curing agent dispersion are added together to the foaming equipment for foaming, wherein the zinc oxide is 5-10 parts and the curing agent is 4-6 parts; (4) Secondary vulcanization process: After radio frequency vulcanization for shaping, it is then vulcanized by steam at 100 degrees Celsius for 30-45 minutes; (5) The finished product is washed, dehydrated and dried.

[0006] In step (2), the pre-vulcanization time is 1-2 hours.

[0007] In step (1), the sulfur emulsion includes the following components by weight: 30-40 parts sulfur, 5-10 parts emulsifier, 80-100 parts deionized water, 6-8 parts accelerator, 3-5 parts antioxidant, 2-3 parts dispersant, and 0.1-0.5 parts KOH aqueous solution.

[0008] Preferably, the sulfurizing agent in the sulfur emulsion is sulfur.

[0009] Preferably, the emulsifier in the sulfur emulsion is disodium salt of N-tallow sulfosuccinate monoester.

[0010] Preferably, the accelerator in the sulfur emulsion is one or a combination of M / MZ / ZDC / DPG.

[0011] Preferably, the antioxidant in the sulfur emulsion is antioxidant WL.

[0012] Preferably, the dispersant in the sulfur emulsion is dispersant N, with the chemical name: sodium methylene bisnaphthalene sulfonate.

[0013] This sulfur emulsion contains emulsifiers, which not only ensure that the sulfur is evenly dispersed in the natural latex, but also allow the sulfur to quickly and fully react with the latex through ultrasonic heating, resulting in a high foam ratio and thus obtaining a latex sponge with a high latex content.

[0014] In step (2), the ultrasonic power is 20-80kHz.

[0015] The natural latex has a solids content of 60% and an ammonia content of 0.2%.

[0016] The potassium oleate solution has a solid content of 20%.

[0017] The solid content of the potassium ricinoleate solution is 35%.

[0018] The zinc oxide is a 50% zinc oxide dispersion.

[0019] The curing agent is a mixture of sodium fluorosilicate and water, with a mixing ratio of 14-20:75-80.

[0020] The present invention provides a high-latex-content natural latex sponge production process that allows sulfur to be evenly dispersed in the natural latex. Ultrasonic waves are then used to ensure that the sulfur fully reacts with the latex, effectively shortening the latex pre-curing time and increasing the foaming ratio. This not only significantly improves production efficiency and maintains the various properties of latex products, but also reduces the amount of sulfur used and produces natural latex products with a higher latex content. Detailed Implementation

[0021] A production process for high-latex-content natural latex sponge includes the following steps: (1) Raw material preparation and dispersion: After the raw materials are prepared and stirred evenly according to the formula, they are stirred at 26-30 degrees Celsius for 2-3 hours to carry out preliminary stirring and dispersion; The raw materials comprise the following components in parts by weight: natural latex: 100 parts; sulfur emulsion: 3-4 parts; potassium oleate solution: 2-5 parts; potassium castor oil solution: 0.5-2 parts; potassium pyrophosphate: 0.1-5 parts; (2) Ultrasonic pre-vulcanization process: The dispersed mixed latex liquid is introduced into a tank container that is ultrasonically vibrated and dispersed, and ultrasonic vibration vulcanization is continued at 28-30 degrees Celsius for 1-2 hours. (3) The prepared pre-vulcanized latex, zinc oxide and curing agent dispersion are added together to the foaming equipment for foaming, wherein the zinc oxide is 5-10 parts and the curing agent is 4-6 parts; (4) Secondary vulcanization process: After radio frequency vulcanization for shaping, it is then vulcanized by steam at 100 degrees Celsius for 30-45 minutes; (5) The finished product is washed, dehydrated and dried.

[0022] The latex sponge products produced by ultrasonic dispersion and vulcanization using the sulfur emulsion of this invention have the following advantages: easy foaming, high expansion ratio, light density, and high latex content.

[0023] Example 1 A production process for high-latex-content natural latex sponge includes the following steps: (1) According to the sulfur emulsion formula, the following materials are added to the high-speed dispersing sand mill in sequence: 30-40 parts sulfur vulcanizing agent, 8 parts DPG / M / ZDC accelerator, 5 parts antioxidant, 3 parts N dispersant, 0.05 parts KOH solution (20%), grind for 60 min, then add 10 parts emulsifier and disperse for later use.

[0024] (2) Raw material preparation and pre-vulcanization. The raw materials are prepared according to the formula and stirred for 2 hours, maintaining the latex temperature at 26 degrees Celsius. The raw materials are made from the following components in parts by weight: Natural latex: 100 parts; sulfur emulsion: 4 parts; Potassium oleate: 4 parts; potassium castor oil solution: 1 part; Potassium pyrophosphate: 0.1 parts; (3) Add the latex to a container equipped with an ultrasonic generator for ultrasonic pre-vulcanization treatment, maintain the pre-vulcanization latex temperature at 28°C, and vulcanize using ultrasonic vibration for 1 hour at an ultrasonic power of 35 kHz; (4) Latex foaming: The pre-vulcanized latex prepared above, zinc oxide, and curing agent are added together in a certain proportion to a foaming device for foaming, wherein the zinc oxide is 5 parts and the curing agent is 4 parts; (5) Secondary vulcanization: After radio frequency vulcanization for shaping, it is then vulcanized by steam at 100 degrees Celsius for 35 minutes; (6) The finished product is washed, dehydrated and dried (i.e. dried in an oven).

[0025] (7) Natural latex sponge was obtained, and the final product test was conducted: natural latex content 92%, density 72 kg / m³. 3 Tensile strength: 66 kPa, compression set: 8.1%.

[0026] Example 2 A production process for high-latex-content natural latex sponge includes the following steps: (1) According to the sulfur emulsion formula, the following materials are added to the high-speed dispersing sand mill in sequence: 30-40 parts sulfur vulcanizing agent, 8 parts DPG / M / ZDC accelerator, 5 parts antioxidant, 3 parts N dispersant, 0.05 parts KOH solution (20%), grind for 60 min, then add 10 parts emulsifier and disperse for later use.

[0027] (2) Raw material preparation and pre-vulcanization. The raw materials are prepared according to the formula and stirred for 2 hours, maintaining the latex temperature at 26 degrees Celsius. The raw materials are made from the following components in parts by weight: Natural latex: 100 parts; sulfur emulsion: 3 parts; Potassium oleate: 3 parts; potassium castor oil solution: 0.5 parts Potassium pyrophosphate: 0.1 parts; (3) Add the latex to a container equipped with an ultrasonic generator for ultrasonic pre-vulcanization treatment, maintain the pre-vulcanization latex temperature at 28°C, and vulcanize using ultrasonic vibration for 1 hour at an ultrasonic power of 35 kHz; (4) Latex foaming: The pre-vulcanized latex prepared above, zinc oxide, and curing agent are added together in a certain proportion to a foaming device for foaming, wherein the zinc oxide is 5 parts and the curing agent is 4 parts; (5) Secondary vulcanization: After radio frequency vulcanization for shaping, it is then vulcanized by steam at 100 degrees Celsius for 35 minutes; (6) The finished product is washed, dehydrated and dried (i.e. dried in an oven).

[0028] (7) Natural latex sponge was obtained, and the product was tested: natural latex content 93%, density 70kg / m3, tensile strength 61kPa, compression set 9.2%.

[0029] The methods, steps, and data described in this invention are merely specific embodiments of the invention, serving as a general exposition and illustrative example of the spirit of the invention. Those skilled in the art will recognize the various possibilities of variations or optional embodiments, and various modifications, additions, improvements, or substitutions can be made under the inspiration of the spirit and principles of this invention. It is understood that these modifications, additions, improvements, or substitutions are considered to be included in this invention and do not depart from the spirit of the invention or exceed the scope defined by the appended claims.

Claims

1. A production process for natural latex sponges with high latex content, characterized in that, Includes the following steps: (1) Raw material preparation and dispersion: After the raw materials are prepared and stirred evenly according to the formula, they are stirred at 26-30 degrees Celsius for 2-3 hours to carry out preliminary stirring and dispersion; The raw materials comprise the following components by weight: natural latex: 100 parts; sulfur emulsion: 3-4 parts; potassium oleate solution: 2-5 parts; potassium castor oil solution: 0.5-2 parts; Potassium pyrophosphate: 0.1-5 parts; (2) Ultrasonic pre-vulcanization process: The dispersed mixed latex liquid is introduced into a tank container that is ultrasonically vibrated and dispersed, and ultrasonic vibration vulcanization is continued at 28-30 degrees Celsius for 1-2 hours. (3) The prepared pre-vulcanized latex, zinc oxide and curing agent dispersion are added together to the foaming equipment for foaming, wherein the zinc oxide is 5-10 parts and the curing agent is 4-6 parts; (4) Secondary vulcanization process: After radio frequency vulcanization for shaping, it is then vulcanized by steam at 100 degrees Celsius for 30-45 minutes; (5) The finished product is washed, dehydrated and dried.

2. The production process of high-latex-content natural latex sponge according to claim 1, characterized in that, In step (2), the pre-vulcanization time is 1-2 hours.

3. The production process for high-latex-content natural latex sponge according to claim 1, characterized in that, In step (1), the sulfur emulsion includes the following components by weight: 30-40 parts sulfur, 5-10 parts emulsifier, 80-100 parts deionized water, 6-8 parts accelerator, 3-5 parts antioxidant, 2-3 parts dispersant, and 0.1-0.5 parts KOH aqueous solution.

4. The production process of high-latex-content natural latex sponge according to claim 1, characterized in that, In step (2), the ultrasonic power is 20-80kHz.

5. The production process for high-latex-content natural latex sponge according to claim 1, characterized in that, The natural latex has a solids content of 60% and an ammonia content of 0.2%.

6. The production process of high-latex-content natural latex sponge according to claim 1, characterized in that, The potassium oleate solution has a solid content of 20%.

7. The production process for high-latex-content natural latex sponge according to claim 1, characterized in that, The solid content of the potassium ricinoleate solution is 35%.

8. The production process of high-latex-content natural latex sponge according to claim 1, characterized in that, The zinc oxide is a 50% zinc oxide dispersion.

9. The production process of high-latex-content natural latex sponge according to claim 1, characterized in that, The curing agent is a mixture of sodium fluorosilicate and water, with a mixing ratio of 14-20:75-80.