CN101235166A - Rubber composition modified by resorcinol phenolic resin - Google Patents

Abstract

The invention relates to a modified cured rubber compound which comprises (i) the rubber components of natural rubber or synthetic rubber, (ii) methano donator, (iii) aralkyl substituted phenol resin as the methano acceptor, wherein the aralkyl substituted phenol (resorcin) methano donator resin can be prepared by reacting the substituted or non-substituted phenol compound, vinyl aromatic compound and aldehyde and/or ketone in the presence of organic metal phosphate or phosphite ester catalyst. The inventive methano acceptor has lower smoke degree than R-80 (resorcin-80). And in the tension strength and dynamic mechanical property test, the aralkyl substituted resorcin phenol resin has better performance than R-80 and resorcin-formaldehyde (RF) resin.

Description

Rubber composition modified by resorcinol phenolic resin

technical field

The present invention relates to the preparation of aralkyl-substituted phenolic resins and their use as rubber formulation resins in the manufacture of pneumatic tires, pressure pipes and belts.

Background technique

In the production of reinforced rubber products such as tires and hoses, various reinforcing materials have been used to increase the strength of the rubber products. Typically, these reinforcements are made from rayon, nylon, polyester, steel wire, and fiberglass. Steel wire for these purposes is first plated with brass or zinc. The basic requirement for effective reinforcement is that these reinforcements bond tightly to the rubber. Rubber or rubber compounds achieve maximum reinforcement when maximum bonding occurs between the rubber and the strong material. Because rubber products are constantly flexed and exposed to high temperatures during use, such as in car tires, it is difficult to achieve good adhesion. The rubber and steel wire form a good mechanical bond during vulcanization resulting in excellent initial tack, but due to aging and use of the rubber article, the bonding properties often weaken or disappear completely, leading to premature bond failure. To avoid this, adhesion promoters are often added to maintain a good bond between the rubber or rubber compound and the metal.

Facilitated adhesion between rubber and brass-plated or galvanized steel wire has traditionally been done using a two-component adhesive system, a methylene acceptor and methylene donor system. Previously, resorcinol was used as a methylene acceptor, and hexamethylenetetramine (Hexa) and hexamethoxymethylmelamine (HMMM) were used as methylene donor compounds to facilitate the bonding of steel wire or cord with rubber or Adhesion between rubber compositions. However, Hexa has not been used for a long time in practical applications, because the ammonia gas generated by the decomposition of Hexa will corrode the steel wire and affect the bonding quality. During the vulcanization process, the methylene donor compound generates formaldehyde, which reacts with resorcinol to form a resorcinol-formaldehyde (RF) network structure in situ. The formation of this RF network structure during vulcanization improves the physical, mechanical and adhesive properties of the vulcanizate.

Unfortunately, there are some potential downsides to adding resorcinol to rubber formulations. When resorcinol is not modified, its volatility and smoke are very serious. In order to reduce the fume of resorcinol, resorcinol derivatives, resorcinol-formaldehyde (RF), alkyl-resorcinol-formaldehyde resin, aralkyl-resorcinol- Formaldehyde resins, and are used in rubber formulations, such as tire production. These modified resorcinol derivatives and resins lead to improved mechanical properties of vulcanized rubbers or rubber compositions, adhesive properties of aged and unaged rubbers. Despite these improvements, the content of free resorcinol in resorcinol-formaldehyde resins is still high. Therefore, it is highly desirable to invent a non-smoke or low-smoke resorcinol resin that can be used as a methylene acceptor to enhance the vulcanization, mechanical and adhesive properties of vulcanized rubber compositions.

The primary object of this invention is to provide a low volatility or low fuming methylene acceptor material for use in rubber formulations to enhance vulcanization and mechanical properties. The use of resins with low free monomer content can minimize or eliminate the problem of fuming in rubber formulation applications. In this way, the negative impact on the environment and human health can be greatly reduced through the use of non-smoking resorcinol resins in the tire and non-tire industries.

These rubber compositions can be used in the production of pneumatic tires, hoses and belts.

Contents of the invention

According to the present invention, the aralkyl-modified phenolic resin comprising the following chemical structure is reacted in the presence of organometallic phosphite or phosphite catalysts to generate:

In the above chemical structures, _R1 and _R2 groups can independently be hydrogen, hydroxyl, amino, chlorine, acetyl, benzoyl, alkyl such as methyl, ethyl, propyl, butyl, hexyl, Octyl, nonyl, decyl, dodecyl and pentadecyl, aralkyl such as phenyl, or alkaryl such as alkylphenyl; in the above formula, _R3 and _R4 groups can be independently is hydrogen, alkyl and alkaryl having 1 to 9 carbon atoms.

According to the present invention, the aralkyl-modified phenolic resin can be prepared by the following method: a phenolic compound represented by the following general formula (a) and (1) selected from styrene, α-methylstyrene, p-methyl Reaction of vinyl aromatic compounds of styrene, divinylbenzene, vinylnaphthalene, and vinyltoluene,

In the formula, R _{and R} can be independently hydrogen, hydroxyl, amino, chlorine, acetyl, benzoyl, alkyl such as methyl, ethyl, propyl, butyl, hexyl, octyl, nonyl, Decyl, dodecyl and pentadecyl, aralkyl groups such as benzyl, or alkaryl groups such as alkylphenyl;

Then with (2) one or more aldehyde and/or ketone compounds selected from the group consisting of aqueous formaldehyde, paraformaldehyde, trioxane, acetaldehyde, paraldehyde, butyraldehyde, isobutyraldehyde, hexanal, Octanal, nonanal, crotonaldehyde, cinnamaldehyde, benzaldehyde, furfural, acetone and methyl ethyl ketone, in the presence of an organometallic phosphite or phosphite catalyst represented by the following structural formula (b) or (c) or a mixture thereof Prepared by reaction

In the formula, R independently represents an alkyl group or haloalkyl group having 1 to 20 carbon atoms, an aryl group or a halogenated aryl group having 6 to 12 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms or Haloaralkyl.

The phosphite catalysts useful in the preparation of the phenolic resins of the present invention as methylene donors may be selected from alkyl phosphites or aryl phosphites.

The aryl phosphite catalyst used in the present invention is a phosphite containing the following groups: two aromatic organic ester groups and a hydrogen atom, three aromatic ester groups, or two aromatic ester groups and an alkyl group.

Specific phosphite catalysts include triphenyl phosphite, tri-n-butyl phosphite, triethyl phosphite, trimethyl phosphite, tris(nonylphenyl) phosphite, tris(nonylphenyl) phosphite, (2-Ethylhexyl) ester, tristearyl phosphite, diphenyl-decyl phosphite, diphenyl phosphite, dimethyl phosphite, di-n-butyl phosphite, etc. and their mixtures.

The phosphite catalysts included in the present invention can be used with other catalysts to modify the vulcanization rate, as is well known to those skilled in the art. Co-catalysts that can be used with phosphites can be acids and other latent acid catalysts. Suitable acid catalysts include any of mineral acids such as phosphoric acid, sulfuric acid, or hydrochloric acid, organic acids such as oxalic acid, maleic acid, or acid anhydrides such as maleic anhydride. Strong acids such as sulfuric acid, hydrochloric acid, phosphoric acid, phosphorous acid, benzenesulfonic acid, phenolsulfonic acid, toluenesulfonic acid, methanesulfonic acid, trihaloacetic acid or dihaloacetic acid can be used alone or in combination with the underlying acid. For example, diphenyl phosphite can be pre-reacted with 1-3% of 70% benzenesulfonic acid, methanesulfonic acid or phenolsulfonic acid solution, and used as a catalyst.

The usage amount of the phosphite catalyst can be 0.2-10%, based on the weight of phenol.

The phenolic compounds that can be used to prepare phenolic resins in the present invention are not particularly limited, and preferably include at least one phenol selected from the group consisting of: phenol, o-cresol, m-cresol, p-cresol, xylenol, p-tert-butyl phenylphenol, p-tert-octylphenol, p-phenylphenol, bisphenol-A, bisphenol-F, resorcinol, phloroglucinol, cashew nut shell liquid (CNSL) and m-aminophenol. The most preferred phenolic compound is resorcinol.

Various vinyl aromatic compounds can be used in the preparation of the phenolic resins of the present invention. These compounds may be selected from the group consisting of styrene, α-methylstyrene, β-methylstyrene, p-methylstyrene, divinylbenzene, m-diisopropenylbenzene or p-diisopropenylbenzene, and vinyl naphthalene. The most preferred vinyl aromatic compound is styrene.

In the preparation process of the phenolic resin of the present invention, the phenolic compound represented by the general formula (a) can first undergo an aralkylation reaction with a vinyl aromatic compound, and then alone or together with other phenolic compounds with aldehyde and/or Ketone reaction. Alternatively, the phenolic resin is prepared first and then the vinyl aromatic compound is reacted onto the phenolic resin. In addition to these methods, it is also possible to carry out the aralkylation reaction of part or all of the phenolic compound simultaneously with the reaction with the aldehyde or ketone. However, the preferred option is first aralkylation of phenolic compounds with vinylaromatics followed by reaction with aldehydes or ketones. Formaldehyde is preferred as the aldehyde compound.

The preferred molar ratio of phenol to styrene for preparing the phenolic resin may be 1:0.05˜1:1.5. Similarly, the molar ratio of phenol to aldehyde and/or ketone may be from 1:0.05 to 1:0.7. The molar ratio of phenol, vinyl aromatic compound, aldehyde component is preferably 1:0.05:0.2 to 1:1.5:0.8, in particular 1:0.2:0.3 to 1:1.5:0.7. The three components are preferred resorcinol, formaldehyde and styrene.

The resorcinol novolac resin comprising the chemical structure (a) is useful as a methylene acceptor in rubber compositions for producing pneumatic tires, hoses and belts. Accordingly, this invention provides a modified vulcanized rubber composition comprising (i) a rubber component selected from natural rubber or synthetic rubber, (ii) a methylene donor and (iii) as a methylene acceptor Aralkyl-resorcinol-aldehyde resins.

The rubber component of the present invention may be cis-1,4-polyisoprene (natural or synthetic), polybutadiene, polychloroprene, copolymers of isoprene and butadiene , copolymers of acrylonitrile and butadiene, copolymers of acrylonitrile and isoprene, copolymers of styrene, butadiene and isoprene, isobutylene rubber (butyl) and ethylene-propylene rubber ( EPDM), copolymers of styrene and butadiene and their blends.

The vulcanizable rubber composition of the present invention may contain one or more methylene donors. The term "methylene donor" means a compound capable of generating formaldehyde upon heating, which reacts with the aralkyl-resorcinol-aldehyde resin to form a cross-linked network in the rubber compound. Methylene donors suitable for the present invention include: hexamethylenetetramine, hexaethoxymethylmelamine, hexamethoxymethylmelamine, 2-nitro-2-methyl-1-propanol (NMP) , trioxane, and formaldehyde polymers such as paraformaldehyde.

The weight ratio of methylene donor to methylene donor in the rubber composition of the present invention may vary. Typically, however, the weight ratio will be in the range of about 1:10 to 10:1. The range of the weight ratio is preferably between 1:5 and 5:1.

The methylene acceptors of the present invention are aralkyl-resorcinol-aldehyde resins. These methylene acceptors can be prepared by reacting aralkyl resorcinols with aldehydes and/or ketones in the presence of phosphite catalysts or acid catalysts or mixtures thereof. The reaction of resorcinol and vinyl aromatic compound in the presence of phosphite catalyst or acid catalyst can produce aralkyl resorcinol. Vinylaromatic compounds suitable for use in the aralkylation reaction of the present invention include: styrene, alpha-methylstyrene, divinylbenzene, vinylnaphthalene, m-diisopropenylbenzene or p-diisopropenylbenzene , and vinyl toluene.

In addition to phosphites, acids can also be used as co-catalysts for the aralkylation of resorcinol with vinylaromatics. The applicable acid catalyst for the aralkylation reaction is selected from the following group: inorganic acids such as hydrochloric acid, sulfuric acid, phosphoric acid, phosphorous acid, sulfonic acids such as benzene monosulfonic acid, benzene disulfonic acid, benzene trisulfonic acid, p-toluenesulfonic acid (PTSA ), p-dodecylbenzenesulfonic acid, alkylsulfonic acid, oxalic acid. The amount of the co-catalyst used in the aralkylation reaction is 0.01-10 parts per 100 parts of resorcinol. The reaction temperature used in the aralkylation reaction is preferably 50°C to 180°C.

After the aralkylation of resorcinol with styrene or vinylaromatics, aldehydes or ketones or mixtures of aldehydes and ketones can be added. Examples of suitable aldehydes and ketones include: aqueous aldehydes (37%), paraformaldehyde, solutions containing formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, isobutyraldehyde, hexanal, octanal, nonanal, crotonaldehyde, Benzaldehyde, furfural, acetone and methyl ethyl ketone. The amount of aldehyde and/or ketone used may be 0.05-0.8 mol/1 mol of resorcinol.

The vulcanized rubber composition of the present invention may further contain additives such as carbon black, cobalt salts, stearic acid, silica, sulfur, zinc oxide, fillers, antioxidants and softening oils. Granular fillers such as silica, carbon black, clay, talc, calcium carbonate, and silicates are usually used in rubber as reinforcing materials to improve the physical and mechanical properties of rubber such as modulus, tensile strength, abrasion resistance, Tear performance and dynamic performance.

Usually the vulcanization of the rubber composition is carried out in the presence of a sulfur vulcanizing agent. Examples of suitable sulfur vulcanizing agents include elemental sulfur (free sulfur) or sulfur donor vulcanizing agents such as amine disulfides, polymeric polysulfides or sulfur olefin adducts. Elemental sulfur is the preferred sulfur vulcanizing agent. As known by those skilled in the art, the amount of sulfur vulcanizing agent is in the range of 0.5-10 phr.

Accelerators are usually used to control the time and/or temperature required for the vulcanization reaction to improve vulcanization performance. Suitable accelerator classes include amines, disulfides, guanidines, thioureas, thiazoles, thiurams, sulfenamides, dithiocarbamates and xanthates. The preferred first accelerator is sulfenamide. If a second accelerator is used, the second accelerator is preferably selected from guanidine, dithiocarbamate or thiuram compounds.

The additive of the present invention can be added to the rubber composition according to the addition method of traditional rubber formulation additives, such as hexamethoxymethylmelamine (HMMM). A common method of mixing rubber compositions is mixing with a Banbury mixer. A typical method is that the first non-reactive additives are mixed with the rubber in an internal mixer heated to about 150°C. Vulcanizing agents, promoters and adhesion promoters are added in the second and third mixing steps at a temperature of about 90°C to 150°C.

The present invention also relates to a vulcanizable rubber composition having improved physical and mechanical properties such as tensile modulus, hardness, scorch resistance, dynamic modulus during vulcanization (G'), and Tan δ (hysteresis) .

The vulcanizable rubber mixtures of the invention can be prepared, processed and vulcanized according to known methods. They are very suitable for the production of industrial rubber products, especially those with steel cords or fiber cords as reinforcing supports. Rubber compositions containing aralkyl-resorcinol-formaldehyde resin products can be used in composite products including tires, transmission belts, conveyor belts, printing rollers, rubber heels and soles, rubber wringers, car mats, trucks mud scraper, ball mill lining, pipe material, fan belt, etc. Rubber vulcanizates are especially suitable for the production of steel wire coverings, carcass cords or cover compounds for tires.

Below in conjunction with specific embodiment, further illustrate the present invention. It should be understood that these examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention.

Detailed ways

Example 1

In a 500ml round-bottomed reaction flask equipped with a stirrer, thermometer, reflux condenser and dropping funnel, add 165.1g (1.5 moles) of resorcinol and 10.71g of triphenyl phosphite catalyst (TPP), and heat Blend until melted. Then, 78.1 g (0.93 mol) of formaldehyde aqueous solution was slowly added dropwise to the molten resorcinol within about 90-120 minutes. After the dropwise addition of formaldehyde is completed, the reactant is dehydrated and evaporated to remove all volatiles in the flask until the temperature rises to about 150°C to 160°C. Then, 72.6 g (0.705 moles) of styrene was added to the molten resorcinol-formaldehyde reaction liquid under the condition of increasing temperature, and the dropping time was controlled for about 60 to 120 minutes. After the styrene addition was completed, 5.6 g of NaOH aqueous solution was added to neutralize the acid catalyst. Finally, vacuum dehydration was carried out to obtain a tan resin with a softening point of 108.2°C. HPLC analysis showed that the content of free resorcinol in the resin was 5.4%.

Example 2

In a 500ml round-bottomed reaction flask equipped with a stirrer, thermometer, reflux condenser and dropping funnel, add 165.1g (1.5 moles) of resorcinol and 10.71g of triphenyl phosphite catalyst (TPP), and heat Blend until melted. Then, 71.25 g (0.675 mol) of styrene was added dropwise to the molten resorcinol, and the dropping time was controlled to be 120 minutes. Then slowly add 77.5 g (0.93 moles) of formaldehyde aqueous solution to the molten resorcinol-styrene reaction solution within about 90-120 minutes. After the dropwise addition of formaldehyde is completed, the reactant is dehydrated and evaporated to remove all volatiles in the flask until the temperature rises to about 150°C to 160°C. Then, add 16.5 g (1.15 moles) of styrene to the resorcinol-styrene-formaldehyde reaction liquid in about 60 to 120 minutes under the condition of gradually increasing the temperature. After the dropwise addition, 5.5 g of NaOH aqueous solution was added to neutralize the acid catalyst. Finally, vacuum dehydration was carried out to obtain a tan resin with a softening point of 107°C. HPLC analysis showed that the content of free resorcinol in the resin was 3.4%.

Example 3

In a 500ml round bottom reaction flask equipped with stirrer, thermometer, reflux condenser and dropping funnel, add 165.1g (1.5mol) resorcinol and 10.71g triphenylphosphite catalyst (TPP), and heat Blend until melted. Then, 109.41 g (1.05 mol) of styrene was added dropwise to the molten resorcinol, and the dropping time was controlled to be 120 minutes. Then slowly add 78.75 g (0.945 moles) of formaldehyde solution to the molten resorcinol-styrene reaction liquid within about 90-120 minutes. After all formaldehyde additions were complete, 5.5 g of aqueous NaOH was added to neutralize the acid catalyst. Finally, vacuum dehydration to obtain a red resin with a softening point of 105°C. HPLC analysis showed that the content of free resorcinol in the resin was 0.96%.

The resulting resin contained less than 1% free resorcinol and is considered to be a very low volatility resorcinol resin useful in many applications.

Example 4

In a 500ml round bottom reaction flask equipped with stirrer, thermometer, reflux condenser and dropping funnel, add 165.1g (1.5mol) resorcinol and 10.71g triphenylphosphite catalyst (TPP), and heat Blend until melted. Then, 234 g (2.25 moles) of styrene was added dropwise to the molten resorcinol, and the controlled drop time was 180 minutes. Then slowly add 81.88 g (0.975 mol) of formaldehyde aqueous solution to the molten resorcinol-styrene reaction solution within about 120-150 minutes. After all formaldehyde additions were complete, 5.5 g of aqueous NaOH was added to neutralize the acid catalyst. Finally, vacuum dehydration was carried out to obtain an orange-yellow resin with a softening point of 99°C. HPLC analysis showed that the content of free resorcinol in the resin was zero.

Analytical results clearly indicated that the resin contained no free or unreacted resorcinol. Its application to rubber compositions can minimize or even eliminate the problem of fuming. In the tire and non-tire industries, the use of the non-smoke resorcinol resin prepared in this embodiment can greatly improve the impact on the environment and human health.

Example 5

In a 500ml round bottom reaction flask equipped with stirrer, thermometer, reflux condenser and dropping funnel, add 165.1g (1.5mol) resorcinol and 10.71g triphenylphosphite catalyst (TPP), and heat Blend until melted. Then, 31.2 g (0.3 mol) of styrene was added dropwise to the molten resorcinol, and the dropping time was controlled to be 30-60 minutes. Then, 82.2 g (1.0 mole) of formaldehyde aqueous solution was slowly added to the molten resorcinol-styrene reaction liquid within about 90-120 minutes. After all formaldehyde additions were complete, 5.5 g of aqueous NaOH was added to neutralize the acid catalyst. Finally, vacuum dehydration was carried out to obtain a reddish-brown resin with a softening point of 132°C. HPLC analysis showed that the content of free resorcinol in the resin was 6.1%.

Example 6

In a 500ml round bottom reaction flask equipped with stirrer, thermometer, reflux condenser and dropping funnel, add 110.1g (1.0mol) resorcinol and 7.2g triphenylphosphite catalyst (TPP), and heat Blend until melted. Then, 83.32 g (0.8 mol) of styrene was added dropwise to the molten resorcinol, and the dropping time was controlled to be 120 to 150 minutes. Then slowly add 30.2 g (0.37 moles) of formaldehyde aqueous solution to the molten resorcinol-styrene reaction solution within about 90-120 minutes. After all formaldehyde additions were complete, 3.7 g of aqueous NaOH was added to neutralize the acid catalyst. Finally, vacuum dehydration was carried out to obtain a reddish-brown resin with a softening point of 74°C. HPLC analysis showed that the content of free resorcinol in the resin was 3.4%.

Example 7

In a 500ml round bottom reaction flask equipped with stirrer, thermometer, reflux condenser and dropping funnel, add 165.1g (1.5mol) resorcinol and 3.7g triphenyl phosphite catalyst (TPP), and heat Blend until melted. Then 107.3 g (0.975 mol) of aqueous formaldehyde (40% strength) was slowly added to the molten resorcinol over a period of about 90-120 minutes. After all the formaldehyde was added dropwise and the reaction was over, 1.1 g of NaOH aqueous solution was added to neutralize the acid catalyst. Finally, vacuum dehydration was carried out to obtain a red resin with a softening point of 78°C.

Example 8

In a 500ml round bottom reaction flask equipped with stirrer, thermometer, reflux condenser and dropping funnel, add 165.1g (1.5mol) resorcinol and 3.7g triphenyl phosphite catalyst (TPP), and heat Blend until melted. Then, slowly add 21.75 g (0.375 mol) of anhydrous acetone to the molten resorcinol and make it react completely. Then, within about 90 to 120 minutes, under reflux, slowly add 50.4 g (0.6 moles) of formaldehyde aqueous solution (37% concentration) to the resorcinol-acetone reaction solution. After all the formaldehyde was added dropwise and the reaction was over, 1.0 g of NaOH aqueous solution was added to neutralize the acid catalyst. Finally, vacuum dehydration was carried out to obtain an orange-yellow resin with a softening point of 76°C.

Example 9

In a 500ml round bottom reaction flask equipped with stirrer, thermometer, reflux condenser and dropping funnel, add 165.1g (1.5mol) resorcinol and 3.7g triphenyl phosphite catalyst (TPP), and heat Blend until melted. Then, within about 90 to 120 minutes, under reflux, slowly add 78.1 g (0.93 moles) of formaldehyde aqueous solution (37% concentration) to the molten resorcinol. After all the formaldehyde was added dropwise and the reaction was over, 1.0 g of NaOH aqueous solution was added to neutralize the acid catalyst. Finally, vacuum dehydration was carried out to obtain an orange resin with a softening point of 110°C. HPLC analysis showed a free resorcinol content of 18.9%.

Example 10

In a 500ml round bottom reaction flask equipped with stirrer, thermometer, reflux condenser and dropping funnel, add 165.1g (1.5mol) resorcinol and 3.7g triphenyl phosphite catalyst (TPP), and heat Blend until melted. Then, within about 90 to 120 minutes, under reflux, slowly add 78.1 g (0.93 moles) of formaldehyde aqueous solution (37% concentration) to the molten resorcinol. After all the formaldehyde was added dropwise and the reaction was finished, the reaction mixture was refluxed for another 60 minutes. During this reflux phase, water and volatiles were distilled off the reaction flask at atmospheric pressure and elevated temperature. Then add 59 grams of distilled water to the molten resorcinol-formaldehyde (RF) resin to obtain a crimson resin aqueous solution. The water content of the tested resin solution was 29.5%. The distribution ratio of 4,4'- and 2,4'-methylene bridges in the RF resin measured by the commonly used ¹³ C-NMR analysis method is 80:20.

Example 11

To a 500ml round bottom reaction flask equipped with a stirrer, thermometer, reflux condenser and dropping funnel, add 165.1g (1.5mol) resorcinol and 8.6g tributyl phosphite catalyst (TBP), and heat Blend until melted. Then, 78.2 g (0.75 mol) of styrene was added dropwise to the molten resorcinol, and the dropping time was controlled to be 120 to 150 minutes. Then slowly add 63 g (0.75 moles) of formaldehyde solution to the molten resorcinol-styrene reaction liquid within about 90-120 minutes. After all formaldehyde additions were complete, 2.8 g of aqueous NaOH was added to neutralize the acid catalyst. Finally, vacuum dehydration was carried out to obtain a reddish-brown resin with a softening point of 97°C. HPLC analysis showed that the content of free resorcinol in the resin was 9.4%.

Example 12

Into a 500 ml round bottom reaction flask equipped with a stirrer, thermometer, reflux condenser and dropping funnel, add 165.1 g (1.5 moles) of resorcinol and 8.6 g of diphenyl phosphite catalyst and heat the mixture to melt . Then, 78.2 g (0.75 mol) of styrene was added dropwise to the molten resorcinol, and the dropping time was controlled to be 120 to 150 minutes. Then slowly add 63 g (0.75 moles) of formaldehyde solution to the molten resorcinol-styrene reaction liquid within about 90-120 minutes. After all formaldehyde additions were complete, 2.8 g of aqueous NaOH was added to neutralize the acid catalyst. Finally, vacuum dehydration was carried out to obtain a reddish-brown resin with a softening point of 89°C. HPLC analysis showed that the content of free resorcinol in the resin was 5.6%.

Example 13

Into a 500 ml round bottom reaction flask equipped with a stirrer, thermometer, reflux condenser and dropping funnel, add 165.1 g (1.5 moles) of resorcinol and 8.6 g of triethylphosphite catalyst, and heat the mixture to melt . Then, 78.2 g (0.75 mol) of styrene was added dropwise to the molten resorcinol, and the dropping time was controlled to be 120 to 150 minutes. Then slowly add 63 g (0.75 moles) of formaldehyde solution to the molten resorcinol-styrene reaction liquid within about 90-120 minutes. After all formaldehyde additions were complete, 2.8 g of aqueous NaOH was added to neutralize the acid catalyst. Finally, vacuum dehydration was carried out to obtain a reddish-brown resin with a softening point of 97°C.

Example 14

Into a 500 ml round bottom reaction flask equipped with a stirrer, thermometer, reflux condenser and dropping funnel, 165.1 g (1.5 moles) of resorcinol, 66 g of water and 4.35 g of oxalic acid were added and the mixture was heated. When the temperature rose to about 95°C, slowly add 78.1g (0.93 moles) of formaldehyde solution in about 30 minutes, and the temperature of the mixture was controlled at 90-105°C. After the dropwise addition of formaldehyde was completed, the stirring was continued for another 30 minutes. Then carry out atmospheric pressure and vacuum distillation and dehydration until the temperature of the reaction solution rises to 120-125°C. Then, at 120-130° C., 72.6 g (0.705 mol) of styrene was slowly added, and the dropping time was controlled at 60 minutes. After all the styrene addition was complete, 5.6 g of aqueous NaOH was added to neutralize the acid catalyst. Finally, vacuum dehydration was carried out to obtain a reddish-brown resin with a softening point of 111°C. HPLC analysis showed that the resin had a free resorcinol content of 4.4%.

Example 15

Into a 500 ml round bottom reaction flask equipped with a stirrer, thermometer, reflux condenser and dropping funnel, add 110.1 g (1.0 mole) of resorcinol, 0.8 g of p-toluenesulfonic acid (PTSA) and 2 g of triphenylene Phosphate (TPP) and heat the mixture until melted. Then, 31.2 g (0.3 mol) of styrene was added dropwise to the molten resorcinol, and the dropping time was controlled to be 30 minutes. Then slowly add 50.5 g (0.62 moles) of formaldehyde aqueous solution to the molten resorcinol-styrene reaction liquid within about 90-120 minutes. After all formaldehyde additions were complete, aqueous NaOH was added to neutralize the acid catalyst. Finally, vacuum dehydration was carried out to obtain a reddish-brown resin with a softening point of 121°C. HPLC analysis showed that the free resorcinol content of the resin was 4.3%.

Embodiment 16 (the resorcinol-formaldehyde resin of contrast resin-oxalic acid catalysis)

Into a 500 ml round bottom reaction flask equipped with a stirrer, thermometer, reflux condenser and dropping funnel, 165.1 g (1.5 moles) of resorcinol and 1.5 g of oxalic acid catalyst were added and the mixture was heated to melt. Then, under reflux, slowly add 78.1 g (0.93 moles) of formaldehyde aqueous solution (37% concentration) to the molten resorcinol, and the dropping time is controlled at 90 to 120 minutes. After all the formaldehyde was added dropwise and the reaction was complete, aqueous NaOH was added to neutralize the acid catalyst. Finally, vacuum dehydration was carried out to obtain an orange-yellow resin with a softening point of 112.5°C. HPLC analysis showed that the free resorcinol content of the resin was 17.3%.

Example 17

When resorcinol and resorcinol-based derivatives are used in rubber formulations, resorcinol fuming can be observed during compounding of the rubber composition. This is due to the volatility of resorcinol and the presence of resorcinol as unreacted monomer in derivatives and resins. To determine the volatility of a material, thermogravimetric analysis (TGA) can be used. Table 1 shows the thermal gravimetric analysis data of R-80 and the aralkyl-resorcinol-formaldehyde resin prepared in Example 2 measured under a nitrogen atmosphere.

Table 1   Thermogravimetric Analysis (TGA) data R-80 and resorcinol-styrene-formaldehyde resin (embodiment 2) compound Weight loss (%) 125°C 150℃ 175°C 200℃ 225°C R-80 ^* 0.39 1.52 5.77 17.45 48.31 R-Sty-F 0.6 1.7 3 4.5 7 ^* Commercially available pre-dispersed blend of 80% resorcinol and 20% EPDM   R-Sty-F resin: resorcinol-styrene-formaldehyde resin   Analysis conditions: nitrogen atmosphere, heating rate: 10°C/min

From the results in Table 1, it can be clearly seen that the resin produced by the present invention has a much lower volatility than the commercially available R-80 product of Taixin Company (China) at high temperature. The R-80 is a predispersed blend of 80% resorcinol and 20% EPDM rubber.

Example 18

The natural rubber compositions used in the test were prepared in three steps. Table 2 gives the basic rubber formulations.

Table 2 Tested rubber composition masterbatch parts by weight natural rubber 100 Carbon black (N326) 42 silica 10 Zinc oxide 8 Sulfur (80%) (OT20) 5 Cobalt salt (CN 20.5%) 1.2 Sulfonamide (DCBS) 1.2 Polymerized 1,2-dihydro-2,2,4-trimethylquinoline (TMQ) 0.5 N-(1,2-dimethylbutyl)-N'-phenyl-p-phenylenediamine {6PPD(4020)} 1.5 The resin of R-80 or embodiment 2 or embodiment 16 1.8 HMMM (65%) 4.34

The resin prepared in Example 2 was compared with the RF resin prepared in Example 16 and the commercially available R-80 product to evaluate its performance in natural rubber compounds. Commercially available R-80 is a pre-dispersed blend of 80% resorcinol and 20% EPDM produced by China Tyxin.

In the first step, the rubber masterbatch is mixed at about 150°C in a Banbury mixer. In the second step, the methylene acceptor (with cobalt salt added) prepared according to the method in Example 2 was mixed into an appropriate amount of masterbatch in a Banbury internal mixer at a temperature of about 145°C. In the third step, the insoluble sulfur shown in Table 2, the accelerator and an appropriate amount of HMMM are added and mixed at about 90-100°C. The test compounds were left overnight at a constant room temperature of about 23°C and 50% relative humidity. Then measure its rheometer vulcanization, shape and optimum vulcanization degree at 150°C to evaluate its mechanical properties.

The vulcanization properties were measured with an Alpha Technologies MDR Rheometer according to ASTM D 5289 and ISO6502 test methods at 150°C, 1° arc and 1.67 Hz.

In an oscillating disc rheometer, the compound sample is subjected to an oscillating shear force of constant amplitude. Determines the torque of an oscillating disc embedded in a test compound at the curing temperature. Because changes in rubber or rubber-like formulations are easily measured, the vulcanization test results are intuitive and accurate. One advantage, evident from the table below, is the fast cure rate.

The test data are given in Table 3:

table 3 Compound properties methylene acceptor R-80 Example 2 Example 16 comparison this invention comparison Methylene acceptor (parts) 1.88 1.88 1.88 Methylene Donor {HMMM(65%)} 4.84 4.84 4.84 Rheometer vulcanization (at 150°C, 30 minutes) ML 0.89 0.92 0.74 M H 30.66 27.46 27.83 TS1 1.3 1.4 1.41 TS2 2.3 3.33 3.24 T10 3.12 4.3 4.13 T50 7.11 9.43 8.36 T90 15.1 17.55 16.25 tensile properties 50% modulus (N/mm ² ) 2.9 2.9 2.8 100% modulus (N/mm ² ) 4.6 4.6 4.4 300% modulus (N/mm ² ) 15.4 15.5 15 Tensile strength (N/mm ² ) 21.7 24.2 16.8 elongation at break 405.7 444.3 332.7 Shore A Hardness 81 81 80 Steel cord bonding before aging (Newton) (steel wire: 3+9+15×0.22+1) 1830 1615 1574 Note: R-80 is a commercially available blend of 80% resorcinol and 20% EPDM

It can be clearly seen from the data in Table 3 that compared with the R-80 blend of China Taixin, the aralkyl-resorcinol-formaldehyde resin prepared by the method of the present invention has improved tensile strength.

Example 19

In this example, a Rubber Processing Analyzer (RPA) 2000 was used to measure dynamic mechanical properties.

The RPA2000 is capable of testing uncured and cured rubber with high repeatability and reproducibility. Available tests and subtests include frequency sweep at constant temperature and strain, sulfur change at constant temperature and frequency, strain sweep at constant temperature and frequency, and temperature sweep at constant strain and frequency. The high accuracy of the instrument enables repeated testing of changes in the properties of glue samples.

Storage modulus, G' and Tanδ data are measured by strain sweep and frequency sweep of vulcanized rubber samples at 60°C. The test data are listed in Table 4.

Table 4 Dynamic mechanical properties of plastic samples (Temperature = 60°C) methylene acceptor R-80 Example 2 Example 16 comparison this invention comparison Dynamic Performance (RPA-2000) Strain scan data Storage modulus (G', kPa) 3.5% strain 1983 2040 1912 9.33% strain 1544 1598 1495 15.17% strain 1382 1432 1344 21% strain 1317 1376 1295 Tanδ 3.5% strain 0.222 0.203 0.211 9.33% strain 0.212 0.202 0.207 15.17% strain 0.195 0.185 0.187 21% strain 0.171 0.161 0.164 Frequency Sweep Data Storage modulus (G', kPa) 0.167Hz 1246 1334 1250 1.22Hz 1285 1354 1271 2.28Hz 1308 1363 1280 3.3Hz 1316 1369 1288 Tanδ 0.167Hz 0.138 0.13 0.131 1.22Hz 0.164 0.153 0.155 2.28Hz 0.173 0.162 0.165 3.3Hz 0.174 0.163 0.165 Note: R-80 is a commercially available blend of 80% resorcinol and 20% EPDM

The above data clearly show that the vulcanized compounds incorporating the resins of the present invention exhibit good dynamic properties and low hysteresis while maintaining comparable adhesion properties to RF resins and R-80 resins.

While specific embodiments of the invention have been described above for purposes of illustration, it will be apparent to those skilled in the art that various modifications can be made therein without departing from the scope of the invention.

Claims (10)

1. A modified vulcanized rubber composition comprising: (i) a rubber component selected from natural rubber or synthetic rubber; (ii) a methylene donor; and (iii) Aralkyl-substituted phenolic resins as methylene acceptors, which include the following chemical structures:

In the formula, R1 _{and R2} groups are independently hydrogen, hydroxyl, amino, chlorine, acetyl, benzoyl, alkyl such as methyl, ethyl, propyl, butyl, hexyl, octyl, nonyl , decyl, dodecyl and pentadecyl, aralkyl such as benzyl, or alkaryl such as alkylphenyl; R ₃ and R ₄ groups are independently hydrogen, alkyl and have 1 to 9 Alkaryl of carbon atoms; it is selected from the group consisting of substituted or unsubstituted phenolic compounds: phenol, o-cresol, m-cresol, p-cresol, xylenol, p-tert-butylphenol, p-cresol tert-octylphenol, p-phenylphenol, bisphenol-A, bisphenol-F, resorcinol, phloroglucinol, cashew nut shell liquid and m-aminophenol, with styrene, alpha-methylstyrene , p-methylstyrene, divinylbenzene, vinylnaphthalene, m-diisopropenylbenzene or p-diisopropenylbenzene, and vinylaromatic compounds of vinyltoluene, and then in organometallic phosphite, Prepared by reacting phosphite, or a mixture of phosphite and acidic catalyst, with aldehydes and/or ketones. 2. The composition of claim 1, wherein the organometallic phosphite or phosphite catalyst has the following structures (b), (c) or mixtures thereof:

In the formula, R independently represents an alkyl group or haloalkyl group having 1 to 20 carbon atoms, an aryl group or a halogenated aryl group having 6 to 12 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms or Haloaralkyl. 3. composition as claimed in claim 2, is characterized in that, the phosphite catalyst that is used to prepare methylene acceptor phenolic resin is selected from: alkyl phosphite or aryl phosphite; Phosphite catalysts include: triphenyl phosphite, tri-n-butyl phosphite, triethyl phosphite, trimethyl phosphite, tris(nonylphenyl) phosphite, tri(phosphite 2-ethylhexyl) ester, tristearyl phosphite, diphenyl-decyl phosphite, diphenyl phosphite, dimethyl phosphite, di-n-butyl phosphite, or their mixture. 4. composition as claimed in claim 1 is characterized in that, the aralkyl-resorcinol-formaldehyde methylene acceptor resin of described modification is made by following method, and this method comprises: making methylene Hydroquinone and (1) selected from styrene, α-methylstyrene, p-methylstyrene, divinylbenzene, vinylnaphthalene, m-diisopropenylbenzene or p-diisopropenylbenzene, and ethylene Vinyl aromatic compound of methyl toluene, and (2) formaldehyde reaction, wherein the molar ratio of resorcinol:vinyl aromatic compound:aldehyde is about 1:0.05:0.1 to 1:1.5:0.8. 5. The composition according to claim 1, wherein the aldehyde and/or ketone compound is selected from the group consisting of formaldehyde solution, paraformaldehyde, trioxane, acetaldehyde, paraldehyde, propionaldehyde , butyraldehyde, isobutyraldehyde, hexanal, octanal, nonanal, crotonaldehyde, cinnamaldehyde, benzaldehyde, furfural, acetone and methyl ethyl ketone. 6. composition as claimed in claim 1, is characterized in that, described modified aralkyl-resorcinol-formaldehyde methylene acceptor resin is in phosphite catalyst and another kind as co-catalyst In the presence of acid and latent catalyst; the co-catalyst is selected from the group consisting of inorganic acids such as hydrochloric acid, sulfuric acid, phosphoric acid, phosphorous acid, sulfonic acids such as benzene monosulfonic acid, benzene disulfonic acid, benzene trisulfonic acid, p- Toluenesulfonic acid, p-dodecylbenzenesulfonic acid, alkylsulfonic acid and oxalic acid; the weight ratio of catalyst to co-catalyst for resin preparation is 0.01:1 to 1:0.01. 7. The composition of claim 1, wherein the rubber component is natural or synthetic cis-1,4-polyisoprene, polybutadiene, polychloroprene , copolymer of isoprene and butadiene, copolymer of acrylonitrile and butadiene, copolymer of acrylonitrile and isoprene, copolymer of styrene, butadiene and isoprene, isobutylene Copolymers of rubber (butyl) and ethylene-propylene rubber, styrene and butadiene, and blends thereof. 8. The composition according to claim 1, wherein the methylene donor comprises: hexamethylenetetramine, hexaethoxymethylmelamine, hexamethoxymethylmelamine, 2-nitrate -2-methyl-1-propanol, trioxane, formaldehyde polymers such as paraformaldehyde. 9. composition as claimed in claim 1 is characterized in that, the vulcanized rubber composition of preparation also comprises additive, as sulfur, accelerator, carbon black, cobalt salt, stearic acid, silicon dioxide, zinc oxide, filler, Antioxidant and softening oil. 10. The composition of claim 1, wherein the rubber composition is used in the production of composite products, including tires, transmission belts, conveyor belts, printing rollers, rubber heels and soles, rubber wringers , car mats, truck fenders, ball mill liners, pipes, fan belts and similar products.