CN111117010B

CN111117010B - Foamed rubber composition, vulcanized rubber, and preparation method and application thereof

Info

Publication number: CN111117010B
Application number: CN201811297451.0A
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: 2018-11-01
Filing date: 2018-11-01
Publication date: 2022-03-29
Anticipated expiration: 2038-11-01
Also published as: CN111117010A

Abstract

The invention relates to the field of foamed rubber, and discloses a foamed rubber composition, vulcanized rubber, and a preparation method and application thereof. The composition comprises a rubber matrix, a filler, a vulcanizing agent, a vulcanization accelerator, a vulcanization activator, a foaming agent and an auxiliary foaming agent, and is characterized in that the rubber matrix contains nitrile rubber, polyvinyl chloride and halogenated butyl rubber, and the addition amount of the halogenated butyl rubber is 25-45 parts by weight relative to 100 parts by weight of the nitrile rubber and the polyvinyl chloride. The foamed rubber material prepared from the raw materials has high aperture ratio, and has good low-temperature resistance and damping and sound-insulating effects.

Description

Foamed rubber composition, vulcanized rubber, and preparation method and application thereof

Technical Field

The invention relates to the field of foamed rubber, in particular to a foamed rubber composition, vulcanized rubber, a preparation method and application of the vulcanized rubber.

Background

The nitrile rubber and the polyvinyl chloride (NBR/PVC) rubber are blended and used from the 50 th century, and the forming process is developed and perfected. The blend of the NBR/PVC rubber and the plastic can not only embody the excellent elastic performance and the excellent oil resistance of the NBR, but also integrate the excellent ozone resistance and the excellent chemical resistance of the 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 many journals and patents.

For example, CN 101215391a discloses a preparation method of chlorinated polyethylene modified nitrile rubber foam material, the properties of chlorinated polyethylene are similar to those of PVC, and the foam material prepared by the method significantly improves the ozone resistance, thermal oxidation resistance and aging resistance of NBR foam material; the flame retardance, the wear resistance and the tensile strength of the NBR foam material are improved; the product cost of the NBR foam material is obviously reduced, and good production manufacturability is kept; the method is more environment-friendly; the obtained modified NBR foaming material has good physical property and foam stability; the process is simple and easy to control.

CN 104693494A discloses a foamed rubber and its preparation method, wherein the foamed rubber is prepared from virgin rubber, polyvinyl chloride, reinforcing agent, filler, softener, anti-aging agent, foaming agent, sulfur, accelerator, promoting assistant and the like by extracting according to a certain proportion, and the refining process comprises the following steps: the A virgin rubber can be used: natural rubber, isoprene rubber, SBR, BR, CR, NBR and the like, wherein NBR (nitrile butadiene rubber) is preferred, and nitrile butadiene rubber with the acrylonitrile content of 30-40% and the Mooney viscosity of 40-60 is preferred, and accounts for 35-55%; the polyvinyl chloride accounts for 5 to 30 percent; the C reinforcing agent can be: one or more of pottery clay, magnesium silicate, calcium carbonate, sepiolite, aluminum hydroxide, vulcanized rubber, lignin, carbon black, white carbon black, titanium dioxide and the like are mixed, wherein the optimal proportion of the pottery clay, the white carbon black and the titanium dioxide in the mixing use effect is 8-20%; the softening agent D is styrene-butadiene rubber or butadiene rubber, and accounts for 3% -10%; the proportion of the antioxidant E, namely A or D, is 0.5 to 1 percent; the F vulcanizing agent can use sulfide (sulfur), peroxide and metal oxide, wherein the sulfide (sulfur) is the optimal, and the proportion is 0.5-1.5%; the G vulcanization accelerator can use organic accelerator and inorganic accelerator, wherein the organic accelerator has the optimal effects of DC, DM and TMTD, and the proportion is 0.3% -1.2%; zinc oxide or stearic acid is used as the H vulcanization accelerating assistant, and the proportion is 0.1-0.3%; as the blowing agent, AC, H, OBSH, D, P, T, urea and the like can be used, wherein the effect is best realized by a mixture of AC and H; the proportion of the active ingredients is 0.3 to 2.8 percent.

Elastomer (2012, 22 (4): 61-65) introduces the influence factor research of NBR/PVC rubber-plastic blended foaming material. Research shows that when the mixing ratio of NBR/PVC is 70/30, the foamed product has the highest closed cell rate, the lowest density and the best mechanical property. The density of the foamed product shows an increasing trend along with the increase of the amount of sulfur, under a low-sulfur high-acceleration system, the vulcanization speed and the foaming speed are best matched, the performance of the product is optimal, and under a proper vulcanization system, the density of the foamed product is reduced along with the increase of the amount of the foaming agent. The density of the product is gradually reduced along with the increase of the dosage of the plasticizer DOP, when the dosage of the DOP is 30 parts, the closed cell rate of the obtained product is the highest, the dosage of calcium carbonate has obvious influence on the compression-molded foaming product, and the more the dosage is, the higher the density is.

However, most of the prior foam materials prepared by taking the nitrile rubber as a matrix are almost closed-cell materials, and the mechanical strength and the low-temperature resistance of the nitrile rubber are poor due to the high glass transition temperature of the nitrile rubber.

Disclosure of Invention

The invention aims to overcome the problem of poor low-temperature resistance caused by almost closed cells of a foaming material in the prior art, and provides a foaming rubber composition, vulcanized rubber, a preparation method and application thereof. The foamed rubber material has high aperture ratio, and has good low-temperature resistance, mechanical strength and damping and sound-insulating effects.

In order to achieve the above object, according to one aspect of the present invention, there is provided a foamed rubber composition comprising a rubber matrix containing a nitrile rubber, a polyvinyl chloride and a halogenated butyl rubber, in an amount of 25 to 45 parts by weight relative to 100 parts by weight of the nitrile rubber and the polyvinyl chloride, a filler, a vulcanizing agent, a vulcanization accelerator, a vulcanization activator, a foaming agent and a co-foaming agent.

In a second aspect, the present invention provides a method for producing a vulcanized rubber, comprising mixing the components of the foamed rubber composition of the present invention to form a mixed rubber, and subjecting the mixed rubber to a vulcanization treatment.

In a third aspect of the present invention, there is provided a vulcanized rubber obtained by the production method according to the second aspect of the present invention.

In a fourth aspect, the present invention provides a use of the vulcanized rubber according to the third aspect of the present invention for vibration damping and sound insulating materials.

The invention selects the nitrile rubber, the polyvinyl chloride and the halogenated butyl rubber to be mixed as a base material, and is matched with a vulcanization accelerator formed by a sulfenamide accelerator and a dithiocarbamate accelerator. The prepared foam material has high aperture ratio, good low-temperature performance (the brittleness temperature can reach-39.5 to-29.8 ℃), good tensile strength (the tensile strength can reach 3.65 to 3.78MPa), and is particularly suitable for the fields of electric vehicles and the like to prepare the shock-absorbing sound-insulating foam material.

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.

The first aspect of the present invention provides a foamed rubber composition comprising a rubber matrix, a filler, a vulcanizing agent, a vulcanization accelerator, a vulcanization activator, a foaming agent and a co-foaming agent, wherein the rubber matrix contains a nitrile rubber, a polyvinyl chloride and a halogenated butyl rubber, and the amount of the halogenated butyl rubber added is 25 to 45 parts by weight relative to 100 parts by weight of the nitrile rubber and the polyvinyl chloride.

According to the invention, three components of nitrile rubber, polyvinyl chloride and halogenated butyl rubber are matched to form the base material, wherein the addition amount of the halogenated butyl rubber has a large influence on the performance of the final foamed rubber material, and the addition amount of the halogenated butyl rubber is within the range and is matched with other components, so that the prepared foamed rubber material has good aperture ratio, low-temperature resistance and tensile strength.

According to the present invention, it is further preferred that the halogenated butyl rubber is contained in an amount of 30 to 40 parts by weight with respect to 100 parts by weight of the rubber base.

According to the invention, the Mooney viscosity ML (1+8)125 ℃ of the halogenated butyl rubber is preferably from 20 to 50, preferably from 30 to 40. The halogenated butyl rubber is commercially available, for example, brominated butyl rubber available from Yanshan division, petrochemical, China, under the designation BIIR3032, and having a Mooney viscosity ML (1+8) at 125 ℃ of 32. The halogenated butyl rubber with the characteristics is mixed with the nitrile rubber and the polyvinyl chloride to be used as a rubber matrix, and then is matched with other components, so that the tensile strength and the low-temperature resistance of the foamed rubber composition can be further improved, and the holes in the foamed rubber composition are more uniform.

According to the invention, the weight ratio of the nitrile rubber to the polyvinyl chloride is (1-9):1, preferably (1.5-4): 1. the nitrile rubber and the polyvinyl chloride are mixed according to the proportion, and the nitrile rubber and the polyvinyl chloride are mixed with the halogenated butyl rubber more uniformly, so that the tensile strength of the foamed rubber composition can be further improved.

According to the invention, the bound acrylonitrile content of the nitrile rubber is from 10 to 50% by weight, preferably from 20 to 40% by weight, more preferably from 25 to 35% by weight.

Preferably, the Mooney viscosity ML (1+4) of the nitrile rubber is from 60 to 85 at 100 ℃. The nitrile rubber is commercially available, for example, as nitrile rubber manufactured by Russian Bull, under the designation 3365 (denoted as NBR3365) with a bound acrylonitrile content of 33% by weight and a Mooney viscosity ML (1+4) of 65 at 100 ℃.

According to the invention, the nitrile rubber and the polyvinyl chloride are mixed according to the proportion, and the composition is mixed with the halogenated butyl rubber, so that the foamed rubber material has uniform open pores and better mechanical strength.

In the present invention, the polyvinyl chloride is commercially available, for example, polyvinyl chloride manufactured by the Chinese petrochemical Qilu division under the designation S1000, and has an average polymerization degree of 1000 and an average molecular weight of 6.5 ten thousand.

According to the present invention, it is preferable that the vulcanization accelerator includes a sulfenamide type accelerator and a dithiocarbamate type accelerator, and the amount of the vulcanization accelerator added is 1.5 to 8 parts by weight based on 100 parts by weight of the total amount of the nitrile rubber and the polyvinyl chloride;

preferably, the weight ratio of the sulfenamide accelerator to the dithiocarbamate accelerator is 1 (0.5-3). The sulfenamide accelerators of the invention are commercially available, for example N-cyclohexyl-2-benzothiazolesulfenamide available from Shanghai Yongmo chemical Co., Ltd under the designation Accelerator CZ. Dithiocarbamates are commercially available, for example, zinc dimethyldithiocarbamate, available from Shanghai Yongmo chemical Co., Ltd under the designation accelerator ZDMC.

In the invention, the vulcanization accelerator is matched with two accelerators of a sulfenamide accelerator and a dithiocarbamate accelerator, so that the vulcanization time can be shortened, the vulcanization temperature can be reduced, the dosage of a vulcanizing agent can be reduced, and the physical and mechanical properties of the foamed rubber material can be improved by matching the vulcanization accelerator with other components.

Preferably, the filler is at least one of carbon black, white carbon black and calcium carbonate, and the adding amount of the filler is 5 to 50 parts by weight, preferably 10 to 40 parts by weight, and more preferably 20 to 30 parts by weight. Carbon black in the present invention is commercially available, for example, from Zideli chemical technology, Inc. of Dongguan, under the designation N550.

The substances are selected as the filler, the filler is mixed with other raw materials more uniformly, and the filler can be matched with other raw materials, so that the mechanical strength of the foamed rubber material is further improved.

Preferably, the vulcanizing agents are sulfur and zinc oxide, the addition amount of the sulfur is 0.5-3 parts by weight, preferably 1-2 parts by weight, and the addition amount of the zinc oxide is 2-8 parts by weight, preferably 4-6 parts by weight. In the present invention, sulfur is commercially available, for example, Weifang Zhongchang Chemicals Co., Ltd. Zinc oxide is also commercially available, for example, Weifang Hengfeng chemical Limited.

The vulcanizing agent is selected to be matched with sulfur and zinc oxide, and the vulcanizing agent, the vulcanization accelerator, the foaming agent and the auxiliary foaming agent are combined, so that the vulcanization effect of the foamed rubber material can be further improved, and the prepared foamed rubber material has high aperture ratio and good mechanical property.

Preferably, the vulcanization activator is stearic acid, and the addition amount of the vulcanization activator is 2 to 15 parts by weight, preferably 4 to 10 parts by weight. In the present invention, stearic acid is commercially available, for example, Weifang Heng Feng chemical Co., Ltd.

The selection of the vulcanization activator in the present invention is not particularly limited, and it may be any of various vulcanization activators in the art, for example, fatty acid metal soap salt or zinc oxide, and the vulcanization activator is preferably stearic acid.

Preferably, the foaming agent is an inorganic foaming agent and/or an organic foaming agent, and the addition amount of the foaming agent is 2 to 20 parts by weight, preferably 5 to 15 parts by weight.

Preferably, the co-blowing agent is at least one of organic acid, organic acid derivative, urea or urea derivative, and the addition amount of the co-blowing agent is 1 to 20 parts by weight, preferably 5 to 15 parts by weight.

In the invention, the foaming agent can release N at the temperature of 120-200 DEG C₂、CO₂Or NH₃And the blowing agent used in the present invention may be an inorganic blowing agent (such as sodium bicarbonate, ammonium bicarbonate, etc.) or an organic blowing agent (such as azodicarbonamide, trade name: blowing agent AC; N, N' -dinitrosopentamethylenetetramine, trade name: blowing agent H).

The auxiliary foaming agent can be organic acid, organic acid derivative, urea or urea derivative, and the auxiliary foaming agent can also be borax or zinc oxide. Wherein the organic acid can be at least one of stearic acid, oxalic acid or salicylic acid, and the organic acid derivative can be at least one of zinc stearate, calcium oxalate or zinc oxalate; the urea derivative can be selected from biuret and/or ethanolamine.

In 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 realize uniform foaming.

According to the invention, the composition also 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, and the addition amount of the antioxidant is 1-7 parts by weight, preferably 3-5 parts by weight.

The quinoline anti-aging agent can be 2,2, 4-trimethyl-1, 2-dihydroquinoline polymer and is sold as an anti-aging agent RD; the p-phenylenediamine anti-aging agent can be N-cumyl-N' -phenyl p-phenylenediamine which is commercially known as anti-aging agent 4010NA, the naphthylamine anti-aging agent can be N-phenyl-2-naphthylamine which is commercially known as anti-aging agent D, and in addition, imidazole anti-aging agents such as 2-mercaptobenzimidazole which is commercially known as anti-aging agent MB can also be selected. In the invention, the anti-aging agent can be matched with other components 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, and the addition amount of the plasticizer is 5 to 40 parts by weight, preferably 10 to 30 parts by weight.

In the invention, polar plasticizer is selected to be mixed with other components in the raw materials, coumarone resin can be selected as coal tar plasticizer, stearic acid and stearate can be selected as fatty oil plasticizer, phthalate esters such as plasticizer DOP and plasticizer DBP can be selected as synthetic plasticizer, plasticizer DOA and plasticizer DOS can be selected as fatty dibasic acid ester, and plasticizer TCP or plasticizer TOP can be selected as phosphate plasticizer. The rubber modifier is matched with other components in the foaming rubber material to improve the plasticity of raw rubber and improve the processing performance of rubber compound. The plasticizer is preferably the plasticizer DOP and/or the plasticizer DOA.

According to the present invention, 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, and the addition amount of the heat stabilizer is 1 to 10 parts by weight, preferably 3 to 8 parts by weight.

In the invention, the thermal stabilizer can delay the thermal decomposition of polyvinyl chloride and brominated butyl rubber. The content of the heat stabilizer may vary within a wide range, but the properties of the foamed rubber material obtained are optimum within the above range. The lead salt composite stabilizer is a stable system formed by compounding lead salt serving as a main component with barium stearate or calcium stearate.

In the invention, the zinc oxide can be used as a vulcanizing agent, a vulcanizing activator and a co-foaming agent. If zinc oxide is used as at least one of the vulcanizing agent, the vulcanization activator and the co-blowing agent in the reaction, a sufficient amount of zinc oxide is weighed at a time and added to the reaction at the second kneading stage.

In the invention, stearic acid can be used as a vulcanization activator and also can be used as a co-foaming agent. If stearic acid is used as the vulcanization activator and/or co-blowing agent in the reaction, a sufficient amount of stearic acid is weighed out at a time and added to the reaction at the time of the second kneading.

In a second aspect, the present invention provides a method for preparing a vulcanized rubber, comprising mixing the components of the foamed rubber composition of the first aspect of the present invention to form a mix, and vulcanizing the mix.

In the present invention, the kneading process is not particularly limited as long as the raw materials of the respective components of the foamed rubber material 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.

According to a preferred embodiment of the invention, the mixing mode comprises the steps of carrying out primary mixing on other components except the foaming agent, the co-foaming agent, the vulcanizing agent and the vulcanization accelerator in the rubber composition, and then carrying out secondary mixing on the primary mixed masterbatch and other auxiliary agents, so that the phenomena of scorching and early foaming of the obtained mixed rubber can be avoided, the later-stage processing molding is facilitated, and the product obtained after the subsequent vulcanization and foaming has better service performance.

Preferably, the mixing comprises one-stage mixing and two-stage mixing; the first-stage mixing comprises mixing the nitrile rubber, the polyvinyl chloride, the halogenated butyl rubber, the filler, the vulcanization activator, the anti-aging agent, the plasticizer and the heat stabilizer in the foamed rubber composition at 60-80 ℃ for 3-5min to prepare master batch;

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

According to the invention, the first-stage mixing and the second-stage mixing are mixed under the above conditions, so that the prepared foamed rubber material is uniform in material, 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.

According to the present invention, preferably, the vulcanization temperature is 140-; the vulcanization pressure is 3-12MPa, preferably 6-10 MPa; the vulcanization time is 10-40min, preferably 20-30 min.

In the invention, the rubber compound is vulcanized under the conditions, so that the finally prepared foamed rubber material has better material formability and better mechanical property.

Preferably, the vulcanizate is passed through the mill 3 times with a nip of 1/4-1/2 of product thickness.

In a third aspect, the present invention provides a vulcanizate prepared by the process of the present invention.

The vulcanized rubber prepared by the method and the raw material components has the tensile strength of 3-4MPa and the density of 0.025-0.15g/cm³The aperture ratio is 20-40%, and the brittleness temperature is-41.5 to-22.5 ℃.

The fourth aspect of the present invention provides a 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 apparatus according to the invention is shown in table 1:

TABLE 1

Serial number	Device name	Model number	Manufacturer of the product
				1	Internal mixer	BR1600	Farrel America Ltd
2	Open mill	XK-160	Qingdao Xincheng Yiming machine
				3	Curing of flat sheets	XLB-D4004002	Shanghai first rubber machine
4	Universal tension	SHIMADZU,AG-20	Shimadzu Japan Ltd
				5	Density test	XSE204	Switzerland Mettler Co Ltd

In the following examples and comparative examples, the reagents used to prepare the foamed rubber materials were as follows:

nitrile rubber: the designation 3365 (NBR 3365), a bound acrylonitrile content of 33% by weight and a Mooney viscosity ML (1+4) of 65 at 100 ℃; 1865 (designated as NBR1865), a bound acrylonitrile content of 18% by weight, a Mooney viscosity ML (1+4) of 65 at 100 ℃; a designation 4085 (NBR 4085), a bound acrylonitrile content of 40% by weight, a Mooney viscosity ML (1+4) of 85 at 100 ℃; the designation 5085 (NBR 5085), bound acrylonitrile content 50% by weight, Mooney viscosity ML (1+4) at 100 ℃ 85. The nitrile rubbers are all produced by Russian-Spur.

Polyvinyl chloride: the trademark S1000, produced by the Chinese petrochemical Qilu division.

Brominated butyl rubber: the brand 2032 (marked as BIIR3032) produced by the division of Chinese petrochemical Yanshan. Mooney viscosity ML (1+8) at 125 ℃ of 32; the Mooney viscosity ML (1+8) at 125 ℃ of 27, manufactured by Exxon, USA under the trademark 6222 (noted BIIR 6222); the Mooney viscosity ML (1+8) at 125 ℃ is 50, under the designation 2255 (BIIR 2255) from Exxon, USA.

Vulcanizing agent: sulfur is purchased from Hechiojiu chemical industry Co., Ltd in the Weifang; zinc oxide was purchased from Weifang Heng Fengfang chemical Co.

Vulcanization accelerator (b): the promoter CZ and the promoter ZDMC are purchased from Shanghai Yongyun chemical technology Co.

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

Vulcanization activating agent: stearic acid was purchased from Weifang Heng Fengfeng chemical Co.

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 all purchased from Shanghai Crystal pure science and technology, Inc.

An anti-aging agent: 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, a plasticizer DBP, a plasticizer DOS and a plasticizer TCP are all purchased from Jinan Hengrui chemical Co., Ltd.

Thermal stabilizer: the calcium-zinc composite stabilizer and the barium-zinc composite stabilizer are purchased from Shaoyang Tiantang auxiliary chemical Co.

Example 1

The formulation of each component involved in the process of this example is shown in Table 2 (wherein the numerical values are parts by weight based on 100 parts by weight of the total amount of the nitrile rubber and polyvinyl chloride). The preparation method of the vulcanized rubber S1 of the embodiment is specifically as follows:

mixing in the first stage:

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

And (3) second-stage 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 formulation of each component involved in the process of this example is shown in Table 2 (wherein the numerical values are parts by weight based on 100 parts by weight of the total amount of the nitrile rubber and polyvinyl chloride). The preparation method of the vulcanized rubber S2 of the embodiment is specifically as follows:

mixing in the first stage:

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

And (3) second-stage 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 formulation of each component involved in the process of this example is shown in Table 2 (wherein the numerical values are parts by weight based on 100 parts by weight of the total amount of the nitrile rubber and polyvinyl chloride). The preparation method of the vulcanized rubber S3 of the embodiment is specifically as follows:

mixing in the first stage:

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

And (3) second-stage mixing:

setting the initial temperature of an internal mixer to be 60 ℃, setting the rotor speed 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 above-mentioned rubber compound was vulcanized for 10min at 140 ℃ and 12MPa with a flat vulcanizing agent.

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

A vulcanizate S4 was prepared according to example 1, except that the proportions of the components were varied, as shown in Table 2.

Example 5

A vulcanizate S5 was prepared according to example 1, except that the proportions of the components were varied, as shown in Table 2.

Example 6

A vulcanizate S6 was prepared according to the method 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 the accelerator CZ was used as the vulcanization accelerator.

Example 8

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

The amounts of the raw materials added to the vulcanized rubbers S1 to S8 obtained in examples 1 to 8 are shown in Table 2.

Comparative example 1

A vulcanizate D1 was prepared according to the method of example 1, except that no bromobutyl rubber was added.

Comparative example 2

A vulcanizate D2 was prepared according to the method of example 1, except that bromobutyl rubber was added in an amount of 50 parts by weight.

Comparative example 3

A vulcanizate D3 was prepared according to the method of example 1, except that bromobutyl rubber was added in an amount of 3 parts by weight.

Comparative example 4

A vulcanized rubber D4 was prepared by following the procedure of example 1, except that the rubber matrix was 100 parts by weight of nitrile rubber and 35 parts by weight of bromobutyl rubber.

Comparative example 5

A vulcanizate D5 was prepared according to the method of example 1, except that the rubber matrix was 100 parts by weight polyvinyl chloride and 35 parts by weight of halogenated butyl rubber.

The amounts of raw materials added for preparing 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, m₁Is a bubbleMass of the froth sample;

m₂the mass of the foam block after water absorption;

ρ_lthe density of the foam block sample;

ρ₀the rubber solid gum density.

(4) Determination of low-temperature brittleness temperature of vulcanized rubber: the brittleness temperature was tested according to the method specified in GB/T1682-.

(5) Testing the sound insulation performance of vulcanized rubber: the sound insulation performance was tested using a four microphone standing wave tube model 7758 manufactured by BRUEL & KJAER, denmark. The test frequency was 50 to 1600HZ and the test temperature was room temperature, and the sound insulation performance was compared between the examples and comparative examples using two data points, 500HZ and 1000 HZ.

TABLE 4

From the results of the above examples, comparative examples, and table 4, it is known that nitrile rubber, polyvinyl chloride, and halogenated butyl rubber are selected as the rubber matrix, and the amount of the halogenated butyl rubber is 25 to 45 parts by weight relative to 100 parts by weight of the nitrile rubber and polyvinyl chloride, and the ratio of the nitrile rubber to the polyvinyl chloride is (1 to 9):1, and the obtained rubber foam material can maintain a certain open porosity after vulcanization, has a low brittleness temperature, has a good low temperature resistance, and has a good sound insulation performance for both high frequency and low frequency sounds on the premise of ensuring a certain tensile strength.

Particularly, the nitrile rubber, the polyvinyl chloride and the halogenated butyl rubber which are formed according to the parts by weight are used as a rubber matrix and are matched with a vulcanization accelerator formed by a sulfenamide accelerator and a dithiocarbamate accelerator, so that the aperture ratio, the low-temperature resistance, the tensile strength and the sound insulation performance of the product can be effectively improved. Tests prove that the rubber foaming material prepared by the invention has better shock absorption performance after vulcanization.

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 combinations of various technical features 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 rubber composition comprising a rubber matrix, a filler, a vulcanizing agent, a vulcanization accelerator, a vulcanization activator, a foaming agent and a co-foaming agent, characterized in that: the rubber matrix contains nitrile rubber, polyvinyl chloride and halogenated butyl rubber, and the addition amount of the halogenated butyl rubber is 25-45 parts by weight relative to 100 parts by weight of the nitrile rubber and the polyvinyl chloride;

the weight ratio of the nitrile rubber to the polyvinyl chloride is (1-9): 1.

2. the foamed rubber composition according to claim 1, wherein the halogenated butyl rubber is contained in an amount of 30 to 40 parts by weight relative to 100 parts by weight of the nitrile rubber and the polyvinyl chloride;

and/or the Mooney viscosity ML (1+8) of the halogenated butyl rubber is 20-50 at 125 ℃.

3. The foamed rubber composition of claim 2, wherein the Mooney viscosity ML (1+8)125 ℃ of the halogenated butyl rubber is from 30 to 40.

4. The foamed rubber composition according to any one of claims 1-3, wherein the weight ratio of the nitrile rubber to the polyvinyl chloride is (1.5-4): 1;

and/or the bound acrylonitrile content of the nitrile rubber is 10-50 wt%;

and/or the Mooney viscosity ML (1+4) of the nitrile rubber is 60-85 at 100 ℃.

5. The foamed rubber composition according to claim 4, wherein the bound acrylonitrile content of the nitrile rubber is 20 to 40 wt%.

6. The foamed rubber composition of claim 5, wherein the bound acrylonitrile content of the nitrile rubber is 25-35 wt%.

7. The foamed rubber composition according to claim 1, wherein the vulcanization accelerator comprises a sulfenamide-based accelerator and a dithiocarbamate-based accelerator, and is added in an amount of 1.5 to 8 parts by weight per 100 parts by weight of the nitrile rubber and the polyvinyl chloride;

and/or the weight ratio of the sulfenamide accelerator to the dithiocarbamate accelerator is 1 (0.5-3).

8. The rubber foam composition according to claim 1, wherein the filler is at least one of carbon black, white carbon, and calcium carbonate, and is added in an amount of 5 to 50 parts by weight based on 100 parts by weight of the nitrile rubber and polyvinyl chloride.

9. The foam rubber composition according to claim 8, wherein the filler is added in an amount of 10 to 40 parts by weight.

10. The foam rubber composition according to claim 9, wherein the filler is added in an amount of 20 to 30 parts by weight.

11. The foamed rubber composition according to claim 1, wherein the vulcanizing agents are sulfur and zinc oxide, and the amount of sulfur is 0.5 to 3 parts by weight and the amount of zinc oxide is 2 to 8 parts by weight, relative to 100 parts by weight of the nitrile rubber and polyvinyl chloride;

and/or the vulcanization activator is stearic acid, and the addition amount of the vulcanization activator is 2-15 parts by weight;

and/or the foaming agent is an inorganic foaming agent and/or an organic foaming agent, and the addition amount of the foaming agent is 2-20 parts by weight;

and/or the auxiliary foaming agent is at least one of organic acid, organic acid derivative, urea and urea derivative, and the addition amount of the auxiliary foaming agent is 1-20 parts by weight.

12. The foam rubber composition according to claim 11, wherein the sulfur is added in an amount of 1 to 2 parts by weight; and/or the addition amount of the zinc oxide is 4-6 parts by weight; and/or the addition amount of the vulcanization activator is 4-10 parts by weight; and/or the addition amount of the foaming agent is 5-15 parts by weight; and/or the addition amount of the auxiliary foaming agent is 5-15 parts by weight.

13. The foamed rubber composition of claim 1, wherein the composition further comprises an anti-aging agent, a plasticizer, and a heat stabilizer; and/or the anti-aging agent is at least one of quinoline anti-aging agent, p-phenylenediamine anti-aging agent and naphthylamine anti-aging agent, and the addition amount of the anti-aging agent is 1-7 parts by weight relative to 100 parts by weight of the nitrile rubber and the polyvinyl chloride;

and/or the plasticizer is at least one of a coal tar plasticizer, a fatty oil plasticizer and a synthetic plasticizer, and the addition amount of the plasticizer is 5-40 parts by weight;

and/or 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, and the adding amount of the heat stabilizer is 1-10 parts by weight.

14. The foam rubber composition according to claim 13, wherein the antioxidant is added in an amount of 3 to 5 parts by weight; and/or the addition amount of the plasticizer is 10-30 parts by weight; and/or the addition amount of the heat stabilizer is 3-8 parts by weight.

15. A method for producing a vulcanized rubber, which comprises kneading the components of the foamed rubber composition according to any one of claims 1 to 14 to form a kneaded rubber, and subjecting the kneaded rubber to a vulcanization treatment.

16. The production method according to claim 15, wherein the kneading includes one-stage kneading and two-stage kneading;

the first-stage mixing comprises the steps of carrying out first mixing on the nitrile rubber, the polyvinyl chloride, the halogenated butyl rubber, the filler, the vulcanization activator, the anti-aging agent, the plasticizer and the heat stabilizer in the foamed rubber composition at the temperature of 60-80 ℃ for 3-5min to obtain master batch;

17. The method as claimed in claim 15 or 16, wherein the vulcanization temperature is 140-180 ℃; the vulcanization pressure is 3-12 MPa; the vulcanizing time is 10-40 min.

18. The method as claimed in claim 17, wherein the vulcanization temperature is 150-160 ℃; and/or the vulcanization pressure is 6-10 MPa; and/or the vulcanization time is 20-30 min.

19. A vulcanized rubber obtained by the production method according to any one of claims 15 to 18.

20. Use of the vulcanized rubber of claim 19 in a vibration damping and sound insulating material.