JPS6169856A - Reactive plasticizer - Google Patents

Abstract

PURPOSE:To provide a reactive plasticizer for rubber, which gives unvulcanized rubber having improved processability and vulcanized rubber having excellent long-term stability when blended with rubber, by blocking terminal hydroxyl groups of a diene polymer contg. a polyether side chain with silyl groups. CONSTITUTION:An alkylene oxide, oxetane or tetrahydrofuran is addition- polymerized to a hydroxyl group-terminated polyene (MW: 500-20,000) (e.g. Poly BD-LM-10, a product of Idemitsu Sekiyu Kagaku K.K.) to form a graft polymer (MW: 600-50,000) contg. polyether and/or polyester side chains. The terminal hydroxyl groups of the graft polymer are substituted with silyl, allyl, aryl, aralkyl or glycidyl groups to obtain a reactive plasticizer.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field to which the invention pertains) The present invention relates to a reactive plasticizer that is blended into rubber, etc., and more specifically, it reduces the viscosity of unvulcanized rubber and improves processability when unvulcanized. In addition, during vulcanization, it reacts with polymers, reinforcing agents, etc. through the vulcanizing agent, making it non-extractable, reducing the decrease in modulus of vulcanized rubber and changes over time, and further improving cold resistance and properties of vulcanized rubber. This invention relates to a reactive plasticizer for rubber that also imparts hydrophilic properties.

(Background of the Invention) Conventionally, plasticizers for rubber include petroleum softeners, such as process oil commonly used in the rubber industry, and ester plasticizers, such as dioctyl phthalate (DOP), dioctyl adipate (DOA), and dibutyl phthalate. (D
BP), natural pine cool, tall oil, vegetable oil, etc. are used, and are used when mixing carbon black and inorganic fillers with rubber, or in addition to polyvinyl chloride etc., soft vinyl chloride etc. There are numerous examples of how to make products, and there are countless introductory books on rubber, compositions, and literature on rubber compounding.

However, these are merely used for a single purpose, such as processing aids and softeners, and may be extracted with solvents after vulcanization, volatilized by heating, or attached to other materials by contact. Due to migration, various problems occur such as not being able to maintain initial physical properties, contaminating or softening other materials, and so on.

(Object of the invention) The present invention improves the processability of unvulcanized rubber, etc.
Improves low-temperature properties without deteriorating physical properties after vulcanization, imparts hydrophilicity, and prevents deterioration of vulcanization (crosslinking) physical properties during red time due to no solvent extraction or heating volatilization. The purpose of this invention is to provide a reactive plasticizer which can be suitably used in various rubber products, particularly tires, belts, hoses, rubber molds, sealants, sealants, etc.

(Structure of the Invention) The object of the present invention is achieved by the reactive plasticizer shown below.

That is, the present invention has a hydroxyl group at the end, and a polydiene structure part and polyether 115 and/or as a main chain in the molecule.
Or a polymer containing a polyester structural moiety, such as a silyl group, an allyl group, a 7-aryl<ary, I
) A reactive plasticizer for rubber having a molecular weight of 600 to 50,000 obtained by capping at least one terminal with at least one group selected from W, an aralkyl group, and a glycidyl group.

The present invention will be described in detail below.

The reactive plasticizer of the present invention is a diene homopolymer having 4 or 5 carbon atoms in the skeleton or a copolymer of a diene and a monomer, and has a molecular weight of 500 to 20,000 and has a functional group at the end or within the molecule. Using a polymer (oligomer) having a starting material as a starting material, a polymer having a terminal water MW obtained by addition polymerizing a single or two or more types of cyclic ether compounds such as ethylene oxide, propylene oxide, oxetane, and tetrahydrofuran to this polymer is roughly added. silyl group, allyl group, aryl group, aralkyl group, or glycidyl group, or a diene polymer having the above-mentioned functional groups and polyether or polyester are reacted with diisocyanate to form a terminal water M group. A urethane polymer having the following formula is obtained, and the same is used, which is blocked with a silyl group, an allyl group, an aryl group, an aralkyl group, a glycidyl group, etc. in the same manner as described above. It goes without saying that when etherifying or esterifying a polymer having a functional group, different ether and/or ester structures can be obtained by appropriately using the ether compounds or ester compounds used alone or in combination. . moreover,
When blocking the terminal, it is possible to introduce an allyl group using benzyl chloride or allyl chloride, or to introduce a glycidyl ether group using epichlorohydrin, and the terminal can be blocked with any functional group.

The diene monomer having 4 or 5 carbon atoms used here is
Butadiene and isoprene are typically used, but other diene monomers can also be used. These diene monomers are also suitably copolymerized with other monomers such as olefins, styrene, acrylonitrile, acrylic esters, methacrylic esters, vinyl esters, and vinyl ethers.

Furthermore, the diene polymer (oligomer) can be obtained with different bonding modes, molecular openings, molecular distribution, number of functional groups, etc. depending on the catalyst selected, polymerization method, etc. Specific compounds include butadiene polymers, butadiene-styrene copolymers, butadiene-acrylonitrile copolymers, butadiene-acrylic acid esters, butadiene-methacrylic acid esters, and various vinyl heptamers. copolymer of or isoprene polymer,
Isoprene-acrylonitrile copolymer, isoprene-
Styrene copolymers and copolymers similar to butadines are used. The structure of butadiene and isoprene is 90% or more of cis 1,4 structure, 10% or more of cis and trans combined and the rest is 1.2 or 3,4 structure, or all 1.2 vinyl structure. is used. There are functional groups having a number of 1.5 to 6.0, but those having a functional group number of about 2.0 to 3.0 are usually used.

When these diene structures are blended into rubber or the like, the bonding mode is selected to some extent depending on the crosslinking system used. In the sulfur-vulcanization accelerator systems commonly used in the rubber industry, 1.
4 bonds are quite an important factor in terms of crosslinking efficiency, but in the case of peroxide crosslinking, 1.2 bonds (in the case of isoprene, 3 bonds)
．． (including 4 bonds), there is no problem at all.

The molecular weight of the polydiene structure part is 500 to 20,000.
If it is less than 500, the reactivity is poor, and if it is less than 20.
If it exceeds 000, the viscosity increases, the processability is poor, and the plasticizing effect is also reduced. Of course, not only the molecular weight of the polydiene structural part but also the molecular weight of the polyether and/or polyester structural part greatly influences the reactivity and plasticity.
Alternatively, the molecular weight including the polyester structure is preferably about 600 to 50,000. Those with a molecular ff of less than 1600 have poor reactivity and cannot be blended into rubber.
Even when heated, nearly all m of the fibers are extracted by solvent extraction, resulting in only a plasticizing effect, and those exceeding 50,000 m are
The processability is poor and the plasticizing effect is also low, so there is not much merit.

Regarding the polyether and/or polyester structure, among the reactive plasticizers of the present invention, it does not directly participate in the reaction of rubber, but rather has a plasticizing effect by not crosslinking, or a hydrophilicity imparting effect as well as a sliding effect. It also plays a role in improving low-temperature properties to some extent. Of course, there are differences in hydrophilicity, compatibility, and low-temperature properties depending on the structure of the polyether and/or polyester portion, and they can be used appropriately depending on the use and purpose.

Furthermore, what is important in the present invention is to block the terminal end of the reactive plasticizer instead of leaving it as active hydrogen. This is a replaced ether type bond.

In addition, the ratio of the polydiene structure part to the polyether and/or polyester structure part is from 10:1 to II ratio.
1 = 10, and if the polyether and/or polyester structural part is less than 1, the plasticizing effect and hydrophilicity will be poor, and if it exceeds 10, there will be less polydiene structural parts to react, and extraction, migration, etc. will easily occur. , the bond with polymers such as rubber is reduced.

Furthermore, the weight ratio of the blocking portion is 1 to 1,000 of the main chain.
If it exceeds 200, the effect of the terminal group is large and in terms of reactivity, only allyl groups are effective for peroxide crosslinking, and general alkyl groups, aryl groups, aralkyl groups, and silyl groups are The disadvantage is that it is completely useless in some respects.

The terminal active hydrogen of the reactive plasticizer of the present invention has poor compatibility with rubber as it is, and even if it is mixed, it may separate after a while, or in some cases, it may separate for a long time.

Furthermore, in rubber vulcanization, there are cases where scorch is accelerated but vulcanization is delayed.

Therefore, 40% or more of the terminal active hydrogen must be composed of blocking moieties, and if it is less than that, the above-mentioned disadvantages will occur.

Improving the compatibility of rubber is also very important for reactivity, and rubbers with double bonds, such as natural rubber (NR), polyisoprene rubber (IR), styrene-butadiene copolymer rubber (SIR) ), polybutadiene rubber (SR), nitrile rubber (NBR), Ri00prene rubber (CR), ethylene-propylene-diene copolymer rubber (EPDM), butyl rubber (I[R), and these rubbers It also has the effect of greatly improving compatibility when blending with other polar rubbers, resulting in new polymer blends. Of course, it is also possible to use acrylic rubber, urethane rubber, fluororubber, hydrin rubber (CHR), etc., which can be peroxide crosslinked even if they do not have double bonds.

In addition, examples of compounding liquid diene polymers into rubber include, for example, Japanese Patent Publication No. 41-8642 and Japanese Patent Application Laid-open No. 49-1
No. 15137, which differs from the plasticizer of the present invention in that the liquid rubber has no functional group. The present applicant also disclosed a rubber composition in which liquid polyisoprene is added to solid rubber in Japanese Patent Publication No. 55-41615. Furthermore, as a rubber composition for a tread, Japanese Patent Application Laid-Open No. 56-81346 discloses an invention in which a liquid diene rubber having 3 to 50% of a component having an ether bond added to the end thereof is mixed into rubber. However, all of these have different structures from the plasticizer of the present invention. Furthermore, mere ether conversion does not necessarily satisfy the compatibility with rubber, reactivity, etc.

(Examples and Experimental Examples of the Invention) The present invention will be described in more detail below with reference to Examples and Experimental Examples.

Example 1 In a Hiooml autoclave equipped with a thermometer and a stirrer, liquid polybutadiene with hydroxyl groups (hydroxyl groups 1i
1 [i91, average molecular weight 1100, product name: Po1y8
DL M-10, Idemitsu Petrochemical Co., Ltd. 1) 345Q
and 1.1g of granulated caustic soda and heated to 100-110℃.
After dehydrating for 2 hours under reduced pressure, the pressure is 3Kg/cti or less,
A 1 mol:1 mol mixture of ethylene oxide and propylene oxide was successively injected at a temperature of 105 to 115°C, and it took 8 hours to inject a total of 153 g.

Thereafter, the mixture was aged at the same temperature for 3 hours to obtain 473 g of a yellow viscous liquid product A. The hydroxyl value of this product A was 65.

Next, a tank ffi 700d with a thermometer and stirrer attached.
147 g of product A (hydroxyl value 65) in a closed reactor
and 17.2 g of triethylamine and 150 i of toluene
J was added and stirred uniformly. In a separate container, a solution was prepared by diluting 18.4 liters of trimethylchlorosilane with 60 g of toluene, and this was pressure-injected into a closed reactor over a period of 1 hour. The temperature rose to 0.degree. C. After completion of dropwise addition, the mixture was aged at 50 to 60.degree. C. for 6 hours.

250 g of the saturated toluene was added, diluted, and allowed to stand, causing the HCJ salt of triethylamine to precipitate. This was filtered and toluene was removed at 85° C. under reduced pressure, yielding 143 g of a yellow viscous transparent liquid product (plasticizer-1). This product has a viscosity of 600 cps (at 20°C) and a specific gravity of 0.
959 < 20°C).

Example 2 Product A (hydroxyl value 65), which is the intermediate product of Example 1, and an aqueous solution of caustic soda (50%) were placed in a closed reactor of fi 7007 equipped with a thermometer and a stirrer.
, sg were charged and dehydrated at 80 to 90°C under reduced pressure for 3 hours. After that, 5.7 g of allyl chloride was added at a pressure of -76 to -
20(:llll-1!II), it was added dropwise at 80-90°C over 1 hour.
1 matured. After removing unreacted allyl chloride under reduced pressure at 3980-90°C, the mixture was neutralized with iMM, diluted with 330 g of toluene, and filtered. Further, when toluene was removed under reduced pressure at 85°C, a yellow viscous transparent liquid product (
112g of plasticizer-2) was obtained. This product had a viscosity of 1300 cps (20°C) and a specific gravity of 0.981.

Example 3 50 g of polypropylene glycol (hydroxyl value 560) with an average molecular weight of 200, 130 g of p-diphenylmethane diisocyanate, and 200 g of toluene were placed in a four-bottle flask with a capacity of 1000 ae and equipped with a thermometer and a stirrer.
I+, 0.02 g of dibutyltin dilaurate was added, and the mixture was stirred at 80°C for 5 hours. After that, the water used in Example 1! Add 650 g of 111-terminated liquid polybutadiene,
After further stirring for 6 hours, toluene was distilled off under reduced pressure and 830Q
A pale yellow viscous liquid product B was obtained. The hydroxyl value of this product B was 47.5.

Next, the product B8 was transferred to a four-loaf flask with a capacity of 20,007 connected to a Dean-Starck type esterification apparatus and a thermometer.
30f11 (hydroxyl group 1i1j47.5), 200 g of l-toluene, 369 g of acrylic acid, 20 g of para-toluenesulfonic acid, 1 hydroquinone (5Ω) were added, and the mixture was reacted at reflux temperature for 7 hours. Thereafter, toluene was removed without refluxing, and as soon as the temperature inside the system reached 120°C, the pressure inside the system was gradually reduced to complete the removal of toluene and 846 g of a yellow, slightly viscous liquid product (plasticizer-3 ) was obtained.

The ester number of this product was 45.7.

Example 4 In the production method of Example 1, styrene-butadiene copolymer (trade name:
A liquid product (Plasticizer-4) was obtained by the same manufacturing method as in Example 1 except that allyl chloride was used in place of tolylmethylchlorosilane. The viscosity of this product is 1500 cps (20°C),
Specific gravity was 0.982.

Example 5 In the production method of Example 1, acrylonitrile-butadiene copolymer (
A liquid product (plasticizer-5) was obtained by the same manufacturing method as in Example 1 except that acetic anhydride was used in place of tolylmethylchlorosilane (trade name: CN-15, manufactured by Arco). The viscosity of this product is 2050 cps (20°C),
Specific gravity was 0.992.

Example 6 A liquid was produced by the same manufacturing method as in Example 1, except that liquid polyisoprene with a terminal hydroxyl group (hydroxyl value 52) having a molecular weight of 2300 was used instead of the liquid polybutadiene with a terminal hydroxyl group. (Plasticizer-6) was obtained.

The product had a viscosity of 750 cps (at 20° C.) and a specific gravity of 0.922.

In the production method of Example 1, CTBN 1300 X 7 (BFG
, manufactured by Chemica 1), Example 1 except that allyl chloride was used in place of tolylmethylchlorosilane.
A liquid product (plasticizer-7) was prepared using the same method as above.The viscosity of this product was 2300 cps (at 20°C).
), and the specific gravity was 0.963.

Rubber compositions were prepared by mixing raw rubber and various compounding agents according to the formulations shown in Table 1. The Mooney viscosity of this rubber composition is J
It was measured according to IS K 6300 and the results are shown in Table 1.

This rubber composition was vulcanized at 138°C for 30 minutes, and the plasticizer extraction rate of the resulting vulcanized rubber is shown in Table 1.

Next, this vulcanized rubber sheet was pressure-bonded to another oil-free rubber sheet, and after contacting the sheet at 70° C. for 20 days, the degree of plasticizer migration was measured. The degree of migration was determined by the acetone extraction rate of a rubber sheet that did not contain oil before contact. In addition, 30% of each vulcanized rubber
The 0% modulus change rate and the apparent Tg change are also shown in Table 1.

Table 1 As shown in Table 1, the rubber compositions of Experimental Examples 2 and 3 containing Plasticizer-1, which is a reactive plasticizer of the present invention, are the experimental examples using aromatic oil as a plasticizer. Compared to the rubber composition No. 1, the plasticizer extraction rate after vulcanization is low, and the acetone extraction rate of other rubber sheets is also low. Changes in 300% modulus and apparent TRI are also low.Furthermore, the rubber composition of Experimental Example 3 containing 20 parts by weight of plasticizer-1 has a lower Mooney viscosity when unvulcanized, and a lower processability when unvulcanized. It turns out that it can be improved.

Experimental Examples 4 to 6 Rubber compositions were prepared by mixing raw rubber and various compounding agents according to the formulations shown in Table 2. The Mooney viscosity of this rubber composition is J
It was measured according to IS K 6300 and the results are shown in Table 2.

This rubber composition was vulcanized at 153° C. for 30 minutes, and 2 g of the obtained vulcanized rubber was extracted with acetone. The results are shown in Table 2. In addition, the amount of extracted dioctyl phthalate (DOP) added as a compounding agent was measured, and the results are shown in Table 2. Furthermore, the low temperature embrittlement point of these vulcanized rubbers after being left at 80°C for 60 days was measured in accordance with JIS K2SO3,
It is shown in Table 2 together with the blank.

Table 2 As shown in Table 2, the rubber compositions of Experimental Examples 5 and 6 using Plasticizer-3, which is the plasticizer of the present invention, had plasticizer DO
Compared to Experimental Example 4, in which a large amount of P was blended, the amount of acetone extracted was lower, and all of the blended DOP was extracted in full, so the rubber compositions of Experimental Examples 4 and 5 contained plasticizer- It can be seen that 3 has remained for quite some time. Also, 8
It can be seen that the reduction rate of the low temperature embrittlement point of the heat-aged bond at 0° C. for 60 days is significantly lower in Experimental Examples 5 and 6 than in Experimental Example 4.

From these results, the plasticizer DOP in the vulcanized rubber volatilizes due to heat aging, raising the low-temperature embrittlement point, but the plasticizer-3, which is the plasticizer of the present invention, does not volatilize, so the low-temperature embrittlement point increases. It doesn't rise. From this, the plasticizer of the present invention has a higher D
It can be seen that it has superior low temperature characteristics compared to OP.

Experimental Examples 7 to 11 Rubber compositions were prepared by mixing raw rubber and various compounding agents according to the formulations shown in Table 3. This rubber composition was vulcanized at 153° C. for 30 minutes, and 2 g of the resulting vulcanized rubber was extracted with acetone. The results are shown in Table 3.

In addition, the low temperature embrittlement point of vulcanized rubber after acetone extraction is determined according to JIS
It was measured in accordance with K6301 and is shown in Table 3 together with the blank. Table 3 also shows changes in hardness.

As shown in Table 3, the rubber compositions of Experimental Examples 8 to 11 containing Plasticizers-4 to 7, which are reactive plasticizers of the present invention, are the experimental examples containing aromatic process oil as a plasticizer. Compared to rubber composition No. 7, the amount of acetone extracted is small. Further, Experimental Examples 8 to 10 have a low IJ1i embrittlement point, and the low-temperature embrittlement point changes only slightly even after acetone extraction. On the other hand, in Experimental Example 7, most of the extraction was done by acetone.
Furthermore, the low temperature embrittlement point after extraction has increased. Also,
Looking at the change in hardness before and after acetone extraction, Experimental Example 7 showed a remarkable change in hardness, whereas Experimental Examples 8 to 11 showed almost no change in hardness and maintained the plasticizing effect. I understand.

(Effects of the Invention) As explained above, by blending the reactive plasticizer of the present invention into rubber, etc., it is possible to improve processability when unvulcanized, and also to improve low-temperature properties, plasticity, hydrophilicity, etc. of the vulcanized model. It has the advantage that physical properties do not change due to solvent extraction over time, continuous heating failure, etc., and the properties imparted do not change significantly because it has a relatively high reactivity.

Therefore, the reactive plasticizer of the present invention can be applied to various rubber products having plasticity, low-temperature properties, hydrophilicity, etc.
It is especially applied to rubber products such as tires, belts, hoses, rubber molds, sealants, and sealants.

Claims (1)

[Claims] 1. A polymer having a hydroxyl group at the end and containing a polydiene structure part and a polyether and/or polyester structure part as the main chain in the molecule is a silyl group, allyl group, aryl group, or aralkyl group. A reactive plasticizer for rubber having a molecular weight of 600 to 50,000 obtained by capping at least one terminal with at least one group selected from a group consisting of a glycidyl group and a glycidyl group. 2. The ratio of the polydiene structural part to the polyether and/or polyester structural part is 10:1 to 1:10.
The reactive plasticizer according to claim 1. 3. The weight ratio of the main chain part and the blocked part is 1000
1 to 5:1. 4. Claims 1 and 2, in which 40% or more of the active hydrogens in the main chain are replaced with blocked moieties.
Reactive plasticizer according to item 3 or item 3.