CN112225960B

CN112225960B - Styrene butadiene rubber-based foamed rubber composition, vulcanized rubber, and preparation method and application thereof

Info

Publication number: CN112225960B
Application number: CN201910636400.4A
Authority: CN
Inventors: 郑方远; 刘苹; 李绍宁; 段海东; 乔勋昌; 刘翠云
Original assignee: Sinopec Beijing Research Institute of Chemical Industry; China Petroleum and Chemical Corp
Current assignee: Sinopec Beijing Research Institute of Chemical Industry; China Petroleum and Chemical Corp
Priority date: 2019-07-15
Filing date: 2019-07-15
Publication date: 2022-09-20
Anticipated expiration: 2039-07-15
Also published as: CN112225960A

Abstract

The invention relates to the field of foamed rubber, and discloses a foamed rubber composition based on styrene-butadiene rubber, vulcanized rubber, a preparation method and application thereof, wherein the composition contains a rubber matrix, a filler, a vulcanizing agent, a vulcanization accelerator, an activator, a foaming agent and a co-foaming agent, the rubber matrix contains nitrile rubber, polyvinyl chloride and styrene-butadiene rubber, the content of the styrene-butadiene rubber is 10-40 parts by weight relative to 100 parts by weight of the nitrile rubber and the polyvinyl chloride, and the weight ratio of the nitrile rubber to the polyvinyl chloride is (1-9): 1. the foaming material prepared from the foaming rubber composition has excellent opening rate, and has better mechanical property and sound insulation effect.

Description

Styrene butadiene rubber-based foamed rubber composition, vulcanized rubber, and preparation methods and applications thereof

Technical Field

The invention relates to the field of foamed rubber, in particular to a foamed rubber composition based on styrene butadiene rubber, a method for preparing vulcanized rubber, the vulcanized rubber prepared by the method and application of the vulcanized rubber in a damping and sound-insulating material.

Background

From the 50 s of the last century, the molding process of blending nitrile rubber and polyvinyl chloride (NBR/PVC) rubber and plastic has been developed and perfected.

The blend of NBR/PVC rubber and plastic can not only embody the excellent elastic performance and the excellent oil resistance of NBR, but also integrate the excellent ozone resistance and the excellent chemical resistance of PVC.

The NBR/PVC rubber-plastic foaming material is generally applied to the aspects of packaging, shock absorption and sound insulation, soles, moving handles, pipeline heat preservation performance and the like of electric appliances.

The rubber is independently used as a base material, the shrinkage rate of the foaming material is larger, but the elasticity is good, and when the resin is independently used as the base material, the elasticity of the foaming material is poorer, but the shrinkage rate is small; the foaming material prepared by blending the rubber and the plastic has the properties of flexibility, portability and the like, and has better performance than a single polymer foaming material.

The NBR/PVC rubber-plastic blended foaming material has flexibility, and the flexible foam heat insulation product has the characteristics of light weight, softness, heat resistance, flame retardance, corrosion resistance, low cost, high efficiency and the like, and has wide market prospect.

Researches aiming at the field of rubber foaming materials, in particular to the field of foaming materials taking nitrile rubber as a matrix have been reported in a plurality of periodicals and patents. However, most of the current foam materials prepared by using nitrile rubber as a matrix are almost closed-cell materials, and the balance between the open-cell rate and the mechanical property is not easy to be considered.

Disclosure of Invention

The invention aims to overcome the defects that the rubber foaming material provided by the prior art is almost completely a closed-cell material and cannot be used as a sound insulation material, and the balance between the open cell ratio and the mechanical property is not easy to be considered.

The foamed rubber material formed by the novel foamed rubber composition provided by the invention has higher aperture ratio and simultaneously has good mechanical property and sound insulation effect.

In order to achieve the above object, a first aspect of the present invention provides a styrene-butadiene rubber-based foamed rubber composition comprising a rubber matrix, a filler, a vulcanizing agent, a vulcanization accelerator, an activator, a foaming agent, and a co-foaming agent, wherein the rubber matrix comprises a nitrile rubber, a polyvinyl chloride, and a styrene-butadiene rubber, the styrene-butadiene rubber is present in an amount of 10 to 40 parts by weight, and the weight ratio of the nitrile rubber to the polyvinyl chloride is (1 to 9): 1.

a second aspect of the present invention provides a method for preparing a vulcanized rubber, comprising: the styrene-butadiene rubber-based foamed rubber composition according to the first aspect of the present invention is produced by mixing the respective components to form a rubber mix, subjecting the obtained rubber mix to a vulcanization treatment, and passing the product obtained after the vulcanization treatment through an open mill.

A third aspect of the present invention provides a vulcanized rubber prepared by the method of the second aspect.

A fourth aspect of the present invention provides the use of the vulcanized rubber of the third aspect in a vibration damping and sound insulating material.

The invention selects the mixture of nitrile rubber, polyvinyl chloride and butadiene styrene rubber in specific proportion as the matrix material, and the foaming material prepared by the foaming rubber composition formed by matching with the vulcanization accelerator has high aperture ratio and good tensile strength, and is particularly suitable for preparing the shock-absorbing and sound-insulating foaming material in the fields of electric appliances, automobiles and the like.

Detailed Description

The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.

As described above, the first aspect of the present invention provides a styrene-butadiene rubber-based foamed rubber composition.

According to the invention, three components of nitrile rubber, polyvinyl chloride and styrene butadiene rubber are adopted to form a base material, wherein the addition amount of the styrene butadiene rubber has a large influence on the performance of the final foamed rubber material, the content of the styrene butadiene rubber is controlled to be 10-40 parts by weight relative to 100 parts by weight of the nitrile rubber and the polyvinyl chloride, and the foamed rubber material prepared from the foamed rubber composition formed by matching with other components has good aperture ratio and tensile strength.

More preferably, the styrene-butadiene rubber is contained in an amount of 20 to 30 parts by weight, relative to 100 parts by weight of the nitrile-butadiene rubber and the polyvinyl chloride. In this preferred case, the foamed rubber composition of the present invention produces a foamed rubber material having more excellent open-cell content and mechanical strength.

More preferably, the weight ratio of the contents of the nitrile rubber and the polyvinyl chloride is (1.5-4): 1. the nitrile rubber and the polyvinyl chloride are mixed according to the proportion, so that the tensile strength of the foam material prepared from the foam rubber composition can be further improved.

According to a particularly preferred embodiment, the Mooney viscosity ML (1+4)100 ℃ of the nitrile rubber is greater than the Mooney viscosity ML (1+4)100 ℃ of the styrene-butadiene rubber, and the difference between the Mooney viscosities ML (1+4)100 ℃ of the nitrile rubber and of the styrene-butadiene rubber is between 15 and 60, preferably between 25 and 55. The inventors of the present invention have found that a vulcanized rubber formed from a rubber composition having such characteristics has a high open porosity and a good sound insulation effect.

Preferably, the styrene-butadiene rubber has a Mooney viscosity ML (1+4) at 100 ℃ of from 30 to 60, more preferably from 40 to 50. The styrene-butadiene rubber with the characteristics, the nitrile-butadiene rubber and the polyvinyl chloride are mixed to be used as a rubber matrix, and then the styrene-butadiene rubber, the nitrile-butadiene rubber and the polyvinyl chloride are matched with other components in the composition, so that the mechanical strength and the aperture ratio of a foaming material prepared from the foaming rubber composition can be further improved. The styrene-butadiene rubber of the present invention can be obtained commercially, for example, styrene-butadiene rubber produced by the company of Qilu petrochemical corporation in China, the trade mark is 1502 (marked as SBR1502), and the Mooney viscosity ML (1+4) is 48 at 100 ℃.

Preferably, the bound acrylonitrile content of the nitrile rubber is 10 to 50 wt.%, more preferably 20 to 40 wt.%, even more preferably 25 to 35 wt.%.

Preferably, the Mooney viscosity ML (1+4) of the nitrile rubber is from 70 to 100 ℃ at 100 ℃. The nitrile rubber is commercially available, for example, as nitrile rubber manufactured by Russian Bull, under the designation 3385 (denoted as NBR3385) in which the bound acrylonitrile content is 33% by weight and the Mooney viscosity ML (1+4) is 85 at 100 ℃.

In the present invention, the average polymerization degree of the polyvinyl chloride is preferably 700-1500, and the average molecular weight is preferably 4-40 ten thousand. The polyvinyl chloride is commercially available, for example, polyvinyl chloride manufactured by the Chinese petrochemical, Qilu division under the trade name S1000, the average polymerization degree is 1000, and the average molecular weight is 6.5 ten thousand.

In order to provide a vulcanized rubber obtained from the composition of the present invention with a higher open-cell content, it is preferable that the vulcanization accelerator is at least one selected from the group consisting of sulfenamide-based vulcanization accelerators and dithiocarbamate-based vulcanization accelerators.

Preferably, the vulcanization accelerator is contained in an amount of 1.5 to 8 parts by weight per 100 parts by weight of the nitrile rubber and the polyvinyl chloride. The vulcanization accelerator with the dosage ratio can enable the obtained foaming material to have more excellent physical and mechanical properties and higher aperture ratio.

According to a preferred embodiment, the vulcanization accelerator is a sulfenamide vulcanization accelerator and a dithiocarbamate vulcanization accelerator in a weight ratio of 1 (0.5-3). The sulfenamide-based vulcanization accelerator of the present invention is commercially available, for example, N-cyclohexyl-2-benzothiazolesulfenamide available from Shanghai Yongmo Hua Kogyo Co., Ltd under the CZ designation. Dithiocarbamates vulcanization accelerators are commercially available, for example zinc dimethyldithiocarbamate from Shanghai Yongtonghua engineering Co., Ltd under the trade name ZDMC.

In the present invention, when a sulfenamide-based vulcanization accelerator and a dithiocarbamate-based vulcanization accelerator in a weight ratio of 1 (0.5 to 3) are used as vulcanization accelerators and combined with other components in the foamed rubber composition of the present invention, the vulcanization time can be further shortened, the vulcanization temperature can be lowered, the amount of a vulcanizing agent to be used can be reduced, and the physical and mechanical properties (for example, tensile strength) of the foamed rubber material can be improved.

Preferably, the filler is selected from at least one of carbon black, white carbon black and calcium carbonate.

The carbon black of the present invention is commercially available, for example, from Zideli chemical technology Co., Ltd, Dongguan, under the designation N550.

Preferably, the filler is contained in an amount of 5 to 50 parts by weight, more preferably 10 to 40 parts by weight, and still more preferably 20 to 30 parts by weight, based on 100 parts by weight of the nitrile rubber and the polyvinyl chloride.

Preferably, the vulcanizing agent is sulfur. The sulfur of the present invention is commercially available, for example, Weifang Zhongchang Chemicals Co., Ltd.

Preferably, the vulcanizing agent is contained in an amount of 0.5 to 5 parts by weight, preferably 1 to 3 parts by weight, based on 100 parts by weight of the nitrile rubber and the polyvinyl chloride.

Preferably, the activator is stearic acid and/or zinc oxide.

According to a preferred embodiment, the activators are stearic acid and zinc oxide, and the stearic acid is present in an amount of 2 to 15 parts by weight, more preferably 4 to 10 parts by weight, relative to 100 parts by weight of the nitrile rubber and the polyvinyl chloride; the content of the zinc oxide is 2 to 10 parts by weight, more preferably 3 to 8 parts by weight.

The zinc oxide and stearic acid of the present invention are commercially available, for example, Weifang Hengfeng chemical Limited.

Preferably, the foaming agent is an inorganic foaming agent and/or an organic foaming agent, and the content of the foaming agent is 2 to 20 parts by weight, more preferably 5 to 15 parts by weight, relative to 100 parts by weight of the nitrile rubber and the polyvinyl chloride.

The blowing agent of the present invention is preferably capable of releasing N at 120- ₂ 、CO ₂ Or NH ₃ And the like.

Preferably, the blowing agent of the present invention is an inorganic blowing agent (e.g., sodium bicarbonate, ammonium bicarbonate, etc.) and/or an organic blowing agent (e.g., azodicarbonamide, trade name: blowing agent AC; N, N' -dinitrosopentamethylenetetramine, trade name: blowing agent H).

In the present invention, there is no particular limitation on the type of the co-blowing agent, as long as the co-blowing agent can be used in combination with the blowing agent to improve the foaming effect. Preferably, the co-blowing agent is at least one of zinc oxide, borax, organic acid and its derivatives, urea and its derivatives, and alcohol amine compounds, and the content of the co-blowing agent is 1 to 20 parts by weight, more preferably 5 to 15 parts by weight, relative to 100 parts by weight of the nitrile rubber and the polyvinyl chloride.

For example, the organic acid may be stearic acid, oxalic acid, or salicylic acid; the urea derivative may be biuret, and the alcohol amine compound may be ethanolamine.

According to the invention, the foaming agent is matched with the auxiliary foaming agent, and the auxiliary foaming agent can further improve the activity of the foaming agent, reduce the foaming temperature of the foaming agent and enable the foaming to be more uniform.

According to a preferred embodiment, the composition of the present invention further comprises an anti-aging agent, a plasticizer and a heat stabilizer.

Preferably, the antioxidant is at least one of quinoline antioxidant, p-phenylenediamine antioxidant and naphthylamine antioxidant.

Preferably, the antioxidant is contained in an amount of 1 to 7 parts by weight, more preferably 3 to 5 parts by weight, based on 100 parts by weight of the nitrile rubber and the polyvinyl chloride.

The quinoline antioxidant can be, for example, 2, 4-trimethyl-1, 2-dihydroquinoline polymer, and is commercially known as antioxidant RD.

The p-phenylenediamine antioxidant can be N-cumyl-N' -phenyl-p-phenylenediamine, and is commercially known as the antioxidant 4010 NA.

The naphthylamine antioxidant can be N-phenyl-2-naphthylamine, and is commercially known as antioxidant D.

The antioxidant of the present invention may also be an imidazole antioxidant, such as 2-mercaptobenzimidazole, sold under the trade name antioxidant MB.

The antioxidant can be matched with other components in the composition to delay the aging behaviors of the foamed rubber material such as thermal oxidation, ozone and the like.

According to the invention, the plasticizer may be a polar plasticizer. Preferably, the plasticizer is at least one of a coal tar plasticizer, a fatty oil plasticizer, and a synthetic plasticizer.

More preferably, the plasticizer is contained in an amount of 5 to 40 parts by weight, and still more preferably 10 to 30 parts by weight, based on 100 parts by weight of the nitrile rubber and the polyvinyl chloride.

In the present invention, a polar plasticizer is selected to be mixed with other components in the composition of the present invention, for example, coumarone resin is selected as a coal tar-based plasticizer, stearic acid and stearate are selected as a fatty oil-based plasticizer, phthalate esters, specifically, plasticizers DOP and DBP are selected as synthetic plasticizers, DOA and DOS are selected as fatty dibasic acid esters, and TCP and TOP are selected as phosphate ester plasticizers. The plasticizer is matched with other components in the foaming rubber material, so that the plasticity of the raw rubber can be improved, and the processability of the rubber compound can be improved.

The zinc oxide may function as both an activator and a co-blowing agent, and when zinc oxide is used as a component of the composition of the present invention, the amount of zinc oxide is not greater than the sum of the maximum amounts of the activator and co-blowing agent as described hereinbefore in the present invention.

The stearic acid may function both as an activator and as a co-blowing agent and as a plasticizer, and when stearic acid is used as a component of the composition of the present invention, the amount of stearic acid is not greater than the sum of the maximum amounts of activator, co-blowing agent and plasticizer as described hereinbefore.

The thermal stabilizer can delay the thermal decomposition of polyvinyl chloride. Preferably, the heat stabilizer is at least one of a lead salt composite stabilizer, a calcium-zinc composite stabilizer, a barium-zinc composite stabilizer and a potassium-zinc composite stabilizer.

According to a preferred embodiment, the heat stabilizer is present in an amount of 1 to 10 parts by weight, more preferably 3 to 8 parts by weight, based on 100 parts by weight of the nitrile rubber and the polyvinyl chloride, in order to optimize the properties of the resulting foamed rubber material.

As previously mentioned, a second aspect of the present invention provides a method of preparing a vulcanizate.

In the present invention, the step of kneading in the production of the vulcanized rubber is not particularly limited as long as the raw materials of the components of the foamed rubber composition can be uniformly mixed. For example, the components of the rubber composition may be simultaneously kneaded, or several of the components may be kneaded first, and then the remaining components may be added to continue kneading.

In order to make the properties of the foamed rubber material obtained more excellent, it is preferable in the present invention that the kneading in the process for producing a vulcanized rubber comprises one-stage kneading and two-stage kneading.

Preferably, the one-stage mixing comprises: and carrying out first mixing on a first component in the composition at a temperature of between 60 and 80 ℃ for 3 to 5min to prepare a master batch, wherein the first component contains a rubber matrix, a filler and an activator, and optionally contains an anti-aging agent, a plasticizer and a heat stabilizer.

Preferably, the two-stage mixing comprises: and carrying out second mixing on a second component in the composition and the master batch at the temperature of 50-60 ℃ for 3-4min to obtain the rubber compound, wherein the second component contains a vulcanizing agent, a vulcanization accelerator, a foaming agent and an auxiliary foaming agent.

By adopting the mixing steps, the phenomena of scorching and advanced foaming of the obtained mixed rubber can be avoided, the later-stage processing and forming are facilitated, and the product obtained after the subsequent vulcanization and foaming has better service performance. And the foamed rubber material prepared by the mixing step is uniform in material quality, and the formed foamed rubber material has good aperture ratio and good mechanical property.

Further, both the first-stage mixing and the second-stage mixing may be carried out in a conventional mixing apparatus, and may be, for example, an open mill or an internal mixer.

Preferably, the conditions of the vulcanization treatment include: the vulcanization temperature is 140-180 ℃, and more preferably 150-160 ℃; the vulcanization pressure is 3MPa to 12MPa, and more preferably 6MPa to 10 MPa; the vulcanization time is 10min-40min, more preferably 20min-30 min.

In order to increase the open pore ratio of the vulcanized rubber obtained, preferably, the step of passing the product obtained after the vulcanization treatment through an open mill comprises: passing the vulcanized product through an open mill at least once, wherein the roller spacing is 1/4-1/2 of the thickness of the product; particularly preferably, the vulcanizate is passed through an open mill, for example 3 times.

As previously mentioned, a third aspect of the invention provides a vulcanizate prepared by the method of the second aspect of the invention.

As described above, the fourth aspect of the present invention provides the use of the vulcanized rubber of the present invention for vibration damping and sound insulating materials.

The present invention will be described in detail below by way of examples.

The device information applied below is shown in table 1.

TABLE 1

Serial number	Device name	Model number	Manufacturer of the product
				1	Internal mixer	BR1600	Rall of American Farad
2	Open mill	XK-160	Qingdao Xincheng Yiming mechanical Co Ltd
				3	Flat vulcanizing machine	XLB-D4004002	Shanghai first rubber machinery plant
4	Universal tensile machine	SHIMADZU,AG-20KNG	Shimadzu Japan Ltd
				5	Density tester	XSE204	Switzerland Mettler Co Ltd
6	Four-microphone standing wave tube	7758	Blue BRUEL of Denmark&KJAER Co Ltd

In the following examples, the reagents used to prepare the foamed rubber material were as follows:

nitrile butadiene rubber: the designation 3385 (noted as NBR3385), a bound acrylonitrile content of 33% by weight, a Mooney viscosity ML (1+4) of 85 at 100 ℃; the designation 1895 (noted as NBR1895), 18% by weight bound acrylonitrile content, Mooney viscosity ML (1+4) at 100 ℃ of 95; the designation 4075 (NBR 4075), bound acrylonitrile content 40% by weight, Mooney viscosity ML (1+4) at 100 ℃ 75. The nitrile rubbers are all produced by Russian-Spur.

Polyvinyl chloride: the product is S1000, the average polymerization degree is 1000, the average molecular weight is 6.5 ten thousand, and the product is produced by China petrochemical Zilu division.

Styrene-butadiene rubber: the product is marked with the number 1502 (marked as SBR1502) and is produced by Chinese petrochemical Qilu division, and the Mooney viscosity ML (1+4) is 48 at 100 ℃; the product is marked by a reference number 1510 (marked as SBR1510) and produced by Chinesemetic-Qilu division of China, and the Mooney viscosity ML (1+4) is 30 at 100 ℃; the Mooney viscosity ML (1+4) is 60 at 100 ℃, which is marked as SBR1609 and produced by Qilu, petrochemical company in China.

Sulfur was purchased from Weifang Zhongheng chemical Co., Ltd.

Zinc oxide and stearic acid were purchased from Weifang Heng Feng chemical Co., Ltd.

Vulcanization accelerator (b): CZC, ZDMC, available from Shanghai Yongji chemical technology, Inc.

Carbon black: the trade name N550 is available from Zideli chemical technology Co., Ltd, Dongguan.

Foaming agent: sodium bicarbonate, foaming agent AC, foaming agent H, all from Foshan gas company Limited.

And (3) auxiliary foaming agent: urea, ethanolamine, and oxalic acid were obtained from Shanghai Crystal purification science and technology, Inc.

The antioxidant RD, the antioxidant 4010NA, the antioxidant D and the antioxidant MB are all purchased from Jiangsu Shengao chemical technology Co.

Plasticizer: coumarone resin, DBP, DOS, and TCP were all available from Jinan Hengrui chemical Co., Ltd.

Thermal stabilizer: the calcium-zinc composite stabilizer (industrial grade product, 25kg package) and the barium-zinc composite stabilizer (industrial grade product, 25kg package) are purchased from Shaoyang Tang auxiliary chemical company Limited.

Example 1

The formulation of each component involved in the process of this example is shown in Table 2 (the numerical values therein are parts by weight based on 100 parts by weight of the total amount of nitrile rubber and polyvinyl chloride, and the amounts of the following raw materials are in kg by weight, that is, 1kg per part by weight, the same applies hereinafter).

The preparation method of the vulcanized rubber S1 of the example is specifically as follows:

first mixing:

setting the initial temperature of an internal mixer to be 70 ℃, setting the rotating speed of a rotor to be 70r/min, adding nitrile rubber, polyvinyl chloride and styrene butadiene rubber into the internal mixer for plastication for 0.5min, then adding carbon black, an activating agent, an anti-aging agent, a plasticizer and a heat stabilizer for continuous mixing for 3min, discharging rubber, and standing for 4h to obtain a section of master batch.

Second mixing:

setting the initial temperature of an internal mixer to be 50 ℃, setting the rotating speed of a rotor to be 60r/min, adding the first-stage master batch, the vulcanizing agent, the vulcanization accelerator, the foaming agent and the co-foaming agent into the internal mixer for mixing for 3min, and discharging rubber.

The rubber material obtained by the method is passed through an open mill with the roll spacing of 0.5mm and the roll temperature of 60 +/-5 ℃ for one time, then the roll spacing is adjusted to 5mm, and the rubber compound obtained is placed for 24 hours after two passes.

And vulcanizing the mixed rubber for 30min on a flat vulcanizing machine with the temperature of 160 ℃ and the pressure of 8 MPa.

The vulcanized product was passed through an open mill 3 times with a nip of 1/3 the thickness of the product, giving a vulcanized rubber designated as S1.

Example 2

The formulations of the components involved in the process of this example are shown in table 2.

The preparation method of the vulcanized rubber S2 of the example is specifically as follows:

first mixing:

setting the initial temperature of an internal mixer to be 60 ℃, setting the rotating speed of a rotor to be 70r/min, adding nitrile rubber, polyvinyl chloride and styrene butadiene rubber into the internal mixer for plastication for 0.5min, then adding carbon black, an activating agent, an anti-aging agent, a plasticizer and a heat stabilizer for continuous mixing for 4.5min, discharging rubber, and standing for 4h to obtain a section of master batch.

Second mixing:

setting the initial temperature of an internal mixer to be 50 ℃, setting the rotating speed of a rotor to be 60r/min, adding the first-stage master batch, the vulcanizing agent, the vulcanization accelerator, the foaming agent and the co-foaming agent into the internal mixer for mixing for 4min, and discharging rubber.

Vulcanizing the mixed rubber for 30min on a flat vulcanizing machine with the temperature of 150 ℃ and the pressure of 6 MPa.

The vulcanized product was passed through an open mill 3 times with a nip of 1/2 the thickness of the product, giving a vulcanized rubber designated as S2.

Example 3

The preparation method of the vulcanized rubber S3 of the example is specifically as follows:

first mixing:

setting the initial temperature of an internal mixer to be 80 ℃, setting the rotating speed of a rotor to be 70r/min, adding nitrile rubber, polyvinyl chloride and styrene butadiene rubber into the internal mixer for plastication for 0.5min, then adding carbon black, an activating agent, an anti-aging agent, a plasticizer and a heat stabilizer for continuous mixing for 2.5min, discharging rubber, and standing for 4h to obtain a section of master batch.

Second mixing:

setting the initial temperature of an internal mixer to be 60 ℃, setting the rotor speed to be 60r/min, adding the primary rubber, the vulcanizing agent, the vulcanization accelerator, the foaming agent and the co-foaming agent into the internal mixer, mixing for 3min, and discharging rubber.

The rubber material obtained by the method is passed once on an open mill with the roller spacing of 0.5mm and the roller temperature of 60 +/-5 ℃, then the roller spacing is adjusted to 5mm, and the rubber compound is placed for 24 hours after passing twice.

The above-mentioned rubber mixtures were vulcanized for 10min on a flat vulcanizing agent at 140 ℃ and 12 MPa.

The vulcanized product was passed through an open mill 3 times with a nip of 1/4 the thickness of the product, giving a vulcanized rubber designated as S3.

Example 4

The formulation of each component in this example is similar to that in example 2, except that the styrene-butadiene rubber used in this example is different in type, as shown in table 2.

Also, this example produced vulcanized rubber S4 in the same manner as in example 2.

Example 5

The formulation of the components involved in this example is similar to that of example 3, except that the nitrile rubber used in this example is of a different type, as shown in Table 2.

Also, this example produced vulcanized rubber S5 in the same manner as in example 3.

Example 6

A vulcanized rubber S6 was prepared by following the procedure of example 1, except that the nitrile rubber and polyvinyl chloride were used in a weight ratio of 1: 4.

example 7

A vulcanized rubber S7 was prepared by following the procedure of example 1, except that only CZ was used as the vulcanization accelerator.

Example 8

A vulcanized rubber S8 was prepared by following the procedure of example 1, except that 4kg of CZ and 8kg of ZDMC were used as the vulcanization accelerators.

Example 9

The formulation of this example is exactly the same as in example 1.

A vulcanized rubber S9 was prepared by following the procedure of example 1, except that the vulcanized article was not passed through an open mill, but was directly tested as a vulcanized rubber S9.

The amounts of the raw materials added to the vulcanized rubbers S1 to S9 obtained in examples 1 to 9 are shown in Table 2.

Comparative example 1

A vulcanized rubber D1 was prepared by the method of example 1, except that styrene-butadiene rubber was not added.

Comparative example 2

A vulcanized rubber D2 was prepared in the same manner as in example 1, except that 50kg of styrene-butadiene rubber was added.

Comparative example 3

A vulcanized rubber D3 was prepared in the same manner as in example 1, except that the styrene-butadiene rubber was added in an amount of 3 kg.

Comparative example 4

Vulcanized rubber D4 was prepared in accordance with the method of example 1, except that the rubber matrix was 100kg of nitrile rubber and 25kg of styrene-butadiene rubber.

Comparative example 5

A vulcanized rubber D5 was prepared in accordance with the procedure of example 1, except that the rubber matrix was 100kg of polyvinyl chloride and 25kg of styrene-butadiene rubber.

Comparative example 6

Vulcanized rubber S1 prepared in CN109749154A from example 1 was used as vulcanized rubber D6 of this comparative example.

Comparative example 7

Vulcanized rubber S1 prepared in CN109747087A from example 1 was used as vulcanized rubber D7 of this comparative example.

The amounts of the raw materials added for the preparation of the vulcanized rubbers D1-D5 in comparative examples 1-5 are shown in Table 3.

TABLE 2

Table 2 (continuation)

TABLE 3

Test example

The vulcanized rubbers prepared in the above examples and comparative examples were tested for properties by the following specific test methods:

(1) tensile strength of vulcanized rubber: the tensile strength was tested by means of a universal tensile machine according to the method specified in GB/T528-2009, where the tensile rate was 500mm/min, the test temperature was 23 ℃, the effective part length of the test specimen was 25mm, and the width was 6 mm. For each set of samples, at least 3 replicates were run and the results were median and are shown in table 4.

(2) Density of vulcanized rubber: the density was measured by a density balance according to the method specified in GB/T533-2008, with a sample mass of not less than 2.5g, and for each set of samples, 2 parallel experiments were performed, with the results averaged, and the results obtained are shown in Table 4.

(3) Opening ratio of vulcanized rubber: the open cell content was obtained by a water absorption experiment. The open porosity K is calculated by the following formula:

in the above formula, m ₁ The mass of the foam block sample;

m ₂ the mass of the foam block after water absorption;

ρ _l the density of the foam block sample;

ρ ₀ the rubber solid gum density.

(4) Measurement of sound insulation amount: a four-microphone standing wave tube with model number 7758, produced by Danish BRUEL & KJAER company, is adopted to test the sound insulation performance of the material, the test frequency is 50-1600 HZ, the test temperature is room temperature, two data points of 500Hz and 1000Hz are taken for each embodiment and comparative example to compare the sound insulation performance, the diameter of a sample is 100mm, and the thickness is 3 mm.

TABLE 4

Serial number	Tensile strength/MPa	Density/g/cm ³	Open hole rate/%)	Sound insulation amount (500Hz)/dB	Sound insulation amount (1000Hz)/dB
						S1	4.12	0.025	41.3	26.1	32.9
S2	3.92	0.031	39.6	25.6	32.7
						S3	4.02	0.033	37.6	24.9	31.8
S4	3.79	0.033	35.9	23.9	30.5
						S5	3.75	0.027	30.2	22.9	28.1
S6	3.68	0.125	22.9	21.1	28.6
						S7	2.74	0.030	26.8	22.8	29.7
S8	3.86	0.032	37.5	24.2	32.9
						S9	4.19	0.027	33.6	23.5	29.4
D1	3.84	0.039	2.5	15.3	23.2
						D2	1.12	0.138	28.3	19.2	26.1
D3	2.89	0.045	4.8	15.9	22.6
						D4	2.23	0.201	12.1	16.2	23.5
D5	1.85	0.15	21.3	18.6	26.3
						D6	3.62	0.029	11.1	14.2	23.9
D7	3.85	0.036	3.2	14.3	20.1

The above results show that the rubber foam material prepared by selecting the nitrile rubber, the polyvinyl chloride and the styrene butadiene rubber in a specific ratio to be used as the rubber matrix can keep relatively excellent aperture ratio on the premise of ensuring that the rubber foam material has certain tensile strength after being vulcanized.

Particularly, the nitrile rubber, the polyvinyl chloride and the styrene-butadiene rubber which are formed according to the parts by weight are used as a rubber matrix and are matched with a vulcanization accelerator component in a composition formed by a sulfenamide vulcanization accelerator and a dithiocarbamate vulcanization accelerator, so that the aperture ratio of a product can be effectively improved, and higher tensile strength is kept.

The preferred embodiments of the present invention have been described above in detail, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, many simple modifications can be made to the technical solution of the invention, including various technical features being combined in any other suitable way, and these simple modifications and combinations should also be regarded as the disclosure of the invention, and all fall within the scope of the invention.

Claims

1. A foamed vulcanized rubber composition based on styrene-butadiene rubber, which comprises a rubber matrix, a filler, a vulcanizing agent, a vulcanization accelerator, an activator, a foaming agent and a co-foaming agent, wherein the rubber matrix comprises nitrile rubber, polyvinyl chloride and styrene-butadiene rubber, the content of the styrene-butadiene rubber is 10-40 parts by weight relative to 100 parts by weight of the nitrile rubber and the polyvinyl chloride, and the content weight ratio of the nitrile rubber to the polyvinyl chloride is (1-9): 1;

the Mooney viscosity ML (1+4)100 ℃ of the nitrile rubber is more than the Mooney viscosity ML (1+4)100 ℃ of the styrene butadiene rubber, and the difference between the Mooney viscosity ML (1+4)100 ℃ of the nitrile rubber and the Mooney viscosity ML (1+4) of the styrene butadiene rubber is 15-60;

the method for preparing the foamed vulcanized rubber composition comprises the following steps: mixing the components in the foamed vulcanized rubber composition to form a mixed rubber, vulcanizing the mixed rubber, and passing the vulcanized product through an open mill;

the step of passing the product obtained after the vulcanization treatment through an open mill comprises the following steps: and (3) passing the vulcanized product through an open mill at least once, wherein the roller spacing is 1/4-1/2 of the thickness of the product.

2. The composition as claimed in claim 1, wherein the styrene-butadiene rubber is contained in an amount of 20-30 parts by weight with respect to 100 parts by weight of the nitrile-butadiene rubber and the polyvinyl chloride.

3. The composition according to claim 1 or 2, wherein the weight ratio of the contents of said nitrile rubber and said polyvinyl chloride is (1.5-4): 1.

4. the composition according to claim 1 or 2, wherein the difference between the mooney viscosities ML (1+4)100 ℃ of the nitrile rubber and the styrene butadiene rubber is 25-55.

5. The composition according to claim 1 or 2, wherein the styrene butadiene rubber has a mooney viscosity ML (1+4)100 ℃ of 30-60.

6. The composition of claim 5, wherein the styrene butadiene rubber has a Mooney viscosity ML (1+4)100 ℃ of 40 to 50.

7. A composition according to claim 1 or 2, wherein the bound acrylonitrile content in the nitrile rubber is 10-50 wt%.

8. The composition according to claim 7, wherein the bound acrylonitrile content in the nitrile rubber is 20-40 wt%.

9. The composition according to claim 8, wherein the bound acrylonitrile content in the nitrile rubber is 25-35 wt%.

10. The composition according to claim 1 or 2, wherein the nitrile rubber has a mooney viscosity ML (1+4)100 ℃ of 70-100.

11. The composition as claimed in claim 1 or 2, wherein the polyvinyl chloride has an average degree of polymerization of 700-1500 and an average molecular weight of 4-40 ten thousand.

12. The composition according to claim 1 or 2, wherein the vulcanization accelerator is selected from at least one of sulfenamide-based vulcanization accelerators and dithiocarbamate-based vulcanization accelerators.

13. The composition according to claim 1 or 2, wherein the vulcanization accelerator is contained in an amount of 1.5 to 8 parts by weight relative to 100 parts by weight of the nitrile rubber and the polyvinyl chloride.

14. The composition according to claim 1 or 2, wherein the vulcanization accelerator is a sulfenamide-based vulcanization accelerator and a dithiocarbamate-based vulcanization accelerator in a weight ratio of 1 (0.5-3).

15. The composition of claim 1 or 2, wherein the filler is selected from at least one of carbon black, white carbon, calcium carbonate.

16. The composition according to claim 1 or 2, wherein the filler is present in an amount of 5-50 parts by weight per 100 parts by weight of the nitrile rubber and the polyvinyl chloride.

17. The composition according to claim 16, wherein the filler is present in an amount of 10-40 parts by weight, relative to 100 parts by weight of the nitrile rubber and the polyvinyl chloride.

18. The composition according to claim 17, wherein the filler is present in an amount of 20-30 parts by weight per 100 parts by weight of the nitrile rubber and the polyvinyl chloride.

19. The composition according to claim 1 or 2, wherein the vulcanizing agent is sulfur.

20. The composition according to claim 1 or 2, wherein the vulcanizing agent is contained in an amount of 0.5 to 5 parts by weight with respect to 100 parts by weight of the nitrile rubber and the polyvinyl chloride.

21. The composition according to claim 20, wherein the vulcanizing agent is contained in an amount of 1 to 3 parts by weight with respect to 100 parts by weight of the nitrile rubber and the polyvinyl chloride.

22. The composition of claim 1 or 2, wherein the activator is stearic acid and/or zinc oxide.

23. The composition according to claim 22, wherein said activators are stearic acid and zinc oxide, and the content of said stearic acid is from 2 to 15 parts by weight with respect to 100 parts by weight of said nitrile rubber and said polyvinyl chloride; the content of the zinc oxide is 2-10 parts by weight.

24. The composition according to claim 23, wherein said stearic acid is present in an amount of 4-10 parts by weight relative to 100 parts by weight of said nitrile rubber and said polyvinyl chloride.

25. The composition according to claim 23, wherein said zinc oxide is present in an amount of 3-8 parts by weight per 100 parts by weight of said nitrile rubber and said polyvinyl chloride.

26. The composition according to claim 1 or 2, wherein the foaming agent is an inorganic foaming agent and/or an organic foaming agent, and the content of the foaming agent is 2 to 20 parts by weight with respect to 100 parts by weight of the nitrile rubber and the polyvinyl chloride.

27. The composition according to claim 26, wherein the blowing agent is present in an amount of 5-15 parts by weight per 100 parts by weight of said nitrile rubber and said polyvinyl chloride.

28. The composition according to claim 1 or 2, wherein the co-blowing agent is at least one of zinc oxide, borax, organic acids and derivatives thereof, urea and derivatives thereof, alcohol amine compounds, and is contained in an amount of 1 to 20 parts by weight with respect to 100 parts by weight of the nitrile rubber and the polyvinyl chloride.

29. The composition according to claim 28, wherein said co-blowing agent is present in an amount of 5-15 parts by weight per 100 parts by weight of said nitrile rubber and said polyvinyl chloride.

30. The composition according to claim 1 or 2, further comprising an anti-aging agent, a plasticizer and a heat stabilizer.

31. The composition according to claim 30, wherein the antioxidant is at least one of a quinoline antioxidant, a p-phenylenediamine antioxidant and a naphthylamine antioxidant, and the content of the antioxidant is 1 to 7 parts by weight relative to 100 parts by weight of the nitrile rubber and the polyvinyl chloride.

32. The composition according to claim 31, wherein the antioxidant is contained in an amount of 3 to 5 parts by weight, relative to 100 parts by weight of the nitrile rubber and the polyvinyl chloride.

33. The composition according to claim 30, wherein the plasticizer is at least one of a coal tar-based plasticizer, a fatty oil-based plasticizer, and a synthetic plasticizer, and the content of the plasticizer is 5 to 40 parts by weight with respect to 100 parts by weight of the nitrile rubber and the polyvinyl chloride.

34. A composition according to claim 33, wherein said plasticizer is present in an amount of 10-30 parts by weight per 100 parts by weight of said nitrile rubber and said polyvinyl chloride.

35. The composition of claim 30, wherein the thermal stabilizer is at least one of a lead salt composite stabilizer, a calcium zinc composite stabilizer, a barium zinc composite stabilizer, and a potassium zinc composite stabilizer, and is contained in an amount of 1 to 10 parts by weight based on 100 parts by weight of the nitrile rubber and the polyvinyl chloride.

36. A composition as claimed in claim 35, wherein said thermal stabilizer is present in an amount of 3-8 parts by weight per 100 parts by weight of said nitrile rubber and said polyvinyl chloride.

37. The composition of claim 1 or 2, wherein the mixing comprises one-stage mixing and two-stage mixing;

the first-stage mixing comprises the following steps: performing first mixing on a first component in the composition at the temperature of 60-80 ℃ for 3-5min to prepare a master batch, wherein the first component contains a rubber matrix, a filler and an activator, and optionally contains an anti-aging agent, a plasticizer and a heat stabilizer;

the two-stage mixing comprises: and carrying out second mixing on a second component in the composition and the master batch at the temperature of 50-60 ℃ for 3-4min to obtain the rubber compound, wherein the second component contains a vulcanizing agent, a vulcanization accelerator, a foaming agent and an auxiliary foaming agent.

38. The composition of claim 1 or 2, wherein the conditions of the vulcanization treatment comprise: the vulcanization temperature is 140-180 ℃; the vulcanization pressure is 3MPa-12 MPa; the vulcanizing time is 10min-40 min.

39. The composition of claim 38, wherein the vulcanization treatment conditions comprise: the vulcanization temperature is 150-160 ℃; the vulcanization pressure is 6MPa-10 MPa; the vulcanizing time is 20min-30 min.

40. A vulcanizate prepared from the foamed vulcanizate composition of any of claims 1 to 39.

41. Use of the vulcanized rubber of claim 40 in a vibration damping and sound insulating material.