JPS6234932A - Reactive plasticizer - Google Patents

Abstract

PURPOSE:To provide the titled plasticizer having adjustable compatibility and reactivity and composed of a compound selected from an NCO-terminated polyene polyol urethane prepolymer terminal-blocked with a specific group and a polyene polyol terminal-blocked with a specific group. CONSTITUTION:The objective plasticizer is composed of a compound selected from (A) an urethane prepolymer obtained e.g. by producing an NCO-terminated urethane prepolymer from a polyene polyol (e.g. polybutadiene glycol) and a diisocyanate (e.g. tolylene diisocyanate) and blocking the terminal NCO with a monofunctional compound containing active hydrogen (e.g. EO adduct of butanol) and (B) a polyene polyol having terminal blocked with a monofunctional isocyanate (preferably a compound obtained by blocking one of NCO group of a diisocyanate with a monofunctional compound containing active hydrogen).

Description

[Detailed description of the invention] <Industrial application field> The present invention relates to reactive plasticizers for rubber.

<Prior Art> Conventionally, reactive plasticizers for rubber include compounds in which a part of the terminal hydroxyl group of a liquid diene compound having a hydroxyl group is etherified with alkylene oxide or other cyclic ether (for example, JP-A-56-813646). There are liquid diene compounds without substituents such as hydroxyl groups (for example, Japanese Patent Publication No. 8462/1983).

<Problems to be solved by the invention> However, etherified liquid diene compounds have a problem of poor compatibility with rubber.On the other hand, liquid diene compounds vary in compatibility and reactivity depending on the type of rubber and use. There was a problem that it was not possible to adjust the

<Means for Solving the Problems> The present inventors have arrived at the present invention as a result of intensive studies on reactive plasticizers for rubber that can freely adjust the compatibility and reactivity depending on the type of rubber and its use. did.

That is, the present invention provides a compound selected from the group consisting of a polyene polyol-based NCO-terminated urethane prepolymer (a1) end-capped with a monofunctional active hydrogen-containing compound, and a polyene polyol (a2) end-capped with a monofunctional isocyanate ( This is a reactive plasticizer for rubber characterized by consisting of A).

The polyene polyol-based NCO-terminated urethane prepolymer (a1) capped with a monofunctional active hydrogen-containing compound is produced by producing an NCO-terminated urethane prepolymer from a polyene polyol and a diisocyanate, and capping the terminal NCO with a monofunctional active hydrogen-containing compound. It is easiest to obtain it by

In the above, polyene polyol is a homopolymer of a conjugated diene having 4 or 5 carbon atoms or a copolymer of a conjugated diene and an ethylenically unsaturated monomer, and is a compound having multiple hydroxyl groups at the terminal or in the main chain. It is.

Conjugated dienes include 1,3-butadiene, isoprene and chloroprene. Preferred among these are 1,3-butadiene and isoprene.

Ethylenically unsaturated monomers used in copolymerization include:
The following may be mentioned.

(a) (Meth)acrylic acid (refers to acrylic acid and/or methacrylic acid. The same description will be used hereinafter.)
and its derivatives: (meth)acrylonitrile, (meth)acrylic acid and their salts, methyl (meth)acrylate, dimethylaminoethyl (meth)acrylate,
(Meth)acrylic acid amide, etc.) Aromatic vinyl monomers: Styrene, α-methylstyrene, etc. (C) Olefinic hydrocarbon monomers: Ethylene, propylene, isobutylene, isoprene, etc. (dl vinyl ester monomers: Vinyl acetate, etc. (ill) Vinyl chloride, vinylidene chloride, etc. (fl Vinyl ether monomer: vinyl methyl ether, etc.) Among these, preferred ethylenically unsaturated monomers include acrylonitrile, methyl methacrylate, styrene, and acrylonitrile and styrene. Particularly preferred are acrylonitrile and a combination of acrylonitrile and styrene.

The weight ratio of conjugated diene to ethylenically unsaturated monomer is usually 100:0 to 5:95.

The production of polyenes containing hydroxyl groups at the terminals, which are conjugated dienes or polymers of conjugated dienes and ethylenically unsaturated monomers, involves the production of conjugated dienes alone using a polymerization initiator that generates radicals containing hydroxyl groups, such as hydrogen peroxide. It is carried out by polymerization or copolymerization of a conjugated diene and an ethylenically unsaturated monomer such as styrene or acrylonitrile. The polyene polyol thus obtained is described in detail in, for example, Japanese Patent Publication No. 30103/1983.

The polyene polyol used in the present invention is preferably in liquid form, the average number of functional groups is usually 2 to 5, preferably 2 to 3, and the molecular weight is usually 400 to eooo, preferably 500 to 5,000. The higher the molecular weight, the higher the compatibility with rubber after being used as a plasticizer, the less likely it is to separate during kneading, and the more crosslinking with rubber will occur. However, when it exceeds 6,000, the viscosity increases, the processability is poor, and the plasticizing effect decreases. Furthermore, if the molecular weight is less than 400, the reactivity with rubber is poor.

Examples of diisocyanates include aromatic diisocyanates [tolylene diisocyanate (abbreviated as TDI),
4.4'-diphenylmethane diisocyanate) (abbreviated as M old), crude MDI, modified MDI, etc.], aliphatic diisocyanates (tetramethylene diisocyanate, hexamethylene diisocyanate, etc.), alicyclic diisocyanates (isophorone diisocyanate, hydrogenated MDI) etc.). Among these, aromatic diisocyanates are preferred, and T
Old, H Old and Crude H Old.

Monofunctional active hydrogen-containing compounds include -hydric alcohols (
01-C22 aliphatic alcohols, such as methyl, ethyl, propyl, butyl, 2-ethylhexyl, lauryl, cetyl, oleyl, stearyl alcohol, etc.; alicyclic alcohols, such as cyclohexyl alcohol; aromatic alcohols, such as benzyl alcohol); Alkylene oxide (abbreviated as AO) adducts [C2 to C4 AO adducts to the above -hydric alcohols, such as ethylene oxide (abbreviated as EO) adducts, propylene oxide (abbreviated as EO) adducts,
PO) adduct, butylene oxide adduct, or random or block adduct of two or more of these (BO and PO, etc.), such as butanol EO/PO (4.0 mol 15.3 mol) adduct (butanol EO/PO (4.0 mol 15.3 mol) adduct (butanol 4.0 moles of EO,
Random adduct with a mixture of 5,3 moles of PO is abbreviated)
, butanol PO 5 mol adduct, butanol PO 5 mol adduct, 2-ethylhexanol EO/PO (5 mol/10 mol) adduct, etc.], alkylphenol AO adduct [phenol EO/PO (7 mol/12 mol) adduct, etc.] , AO adducts of phenols having one or more C1-C20 alkyl groups of 01-C20, such as nonylphenol EO 4 mole adducts, nonylphenol PO
7 molar adduct, octylphenol EO/PO (3,5
15.0 mol) adducts], and mixtures of two or more thereof.

Preferred among these are monohydric alcohols or additives thereof, and particularly preferred are butanol E
O adducts, po adducts and EO/PO adducts.

Further, secondary amines (diethylamine, methyldecylamine, ethylstearylamine, etc.) and their alkylene oxide adducts can also be used.

When producing an NCO-terminated prepolymer, the ratio of O in the polyene polyol to NCO in the diisocyanate is:
Usually 110.5 to 1/1.2, preferably 110.
7 to 1/1.1.

The reaction of a polyene polyol with a diisocyanate and the reaction of blocking NCO with a monofunctional active hydrogen-containing compound are
It may be carried out by a conventional method for urethanization reaction, and the reaction temperature is usually 50 to 150"C, preferably 60 to 120C.During the reaction, if necessary, a solvent containing no active hydrogen (such as toluene, xylene, dimethylformamide, etc.) may be used. etc.) can be used.

In the polyene polyol (C2) end-capped with a monofunctional isocyanate, the monofunctional isocyanate includes an aliphatic monoisocyanate (such as stearyl isocyanate), an aromatic monoisocyanate (such as p-tolyl isocyanate), and -N of one of the diisocyanates.
Examples include those in which the CO group is blocked with the above-mentioned monofunctional active hydrogen-containing compound. Preferred is a diisocyanate in which one of the -NCO groups is blocked with a monofunctional active hydrogen-containing compound. The ratio of NCO of the monoisocyanate to Oll of the polyene polyol during the blocking reaction is usually 0.5/1 to 1.2/1, preferably 0.7/1 to 1, 1/1. The blockade reaction is (
The reaction temperature is the same as in C1), and the same solvent can be used if necessary.

If the compound (A) is represented by a general formula, when the number of functional groups of the polyene polyol is 2,
O-El-OCON! ((+s X2・−1−−−
-----...(11 [In the formula, shi is 140 sho nR (OA sho n, R is a polyethylene glycol residue, A is an alkylene group having 2 to 4 carbon atoms, and n is an integer of 0 or 1 or more. , preferably 0 or 1~
It is an integer of 50. Z is a diisocyanate residue.

Xl, x2 are R' or -ZNIICOX, R' is a monoisocyanate residue, It is an aryl group. n is 0 or an integer of 1 or more, preferably O or an integer of 1 to 50. When R# is an aryl group, n' is an integer of 1 or more. m is O or an integer of 1 or more. , preferably 0 or an integer from 1 to 6.].

When the number of functional groups in the polyene polyol exceeds 2, part or all of 7 in general formula +11 is the general formula, -1- to -
11...-(21 (wherein, R1 is a polyene polyol residue, p is a number from 1 to 6, preferably a number from 1 to 4). Therefore, the compound (A) is usually a compound of the general formula (11) and a part or all of the compounds of the general formula (11) are represented by the general formula (2).
It is a mixture of compounds represented by those substituted with groups represented by.

The reactive plasticizers of the present invention are used alone or in combination with other plasticizers such as process oils and dioctyl phthalate (DOP).

Rubbers to be used as the plasticizer of the present invention include rubbers having double bonds, such as natural rubber (NR), polyisoprene rubber (IR), styrene-butadiene copolymer rubber (SBR), and polybutadiene rubber ( BR), nitrile rubber (NBR), chloroprene rubber (CR), ethylene-propylene-diene copolymer rubber (RPDM)
, butyl rubber (III?), and when these rubbers are blended with other polar rubbers, they have the effect of greatly improving compatibility, resulting in new polymer blends. Of course, it is also possible to use acrylic rubber, urethane rubber, silicone rubber, fluororubber, hydrin rubber (CIIR), etc., which can be peroxide crosslinked even if they do not have double bonds.

The amount of reactive plasticizer used in the present invention is usually 3 to 30%, preferably 5 to 20%, based on the weight of the rubber.

If the amount used is less than 3%, the plasticizing effect will not be exhibited, and if it is more than 30%, the physical properties of the rubber will deteriorate, which is not preferable.

The reactive plasticizer of the present invention can be mixed with rubber when raw rubber is mixed into wires using two rolls or a Banbury mixer, and compounding agents such as fillers, softeners, vulcanizing agents, aging agents, etc. A conventional method such as mixing with an inhibitor or the like may be used. Next, a rubber product is obtained by molding and vulcanizing the compounded rubber obtained by such a method. Vulcanization may also be carried out under normal conditions, for example, 160°C, 15 minutes, 0.1
It is carried out under conditions such as kg/- pressurization.

When the double bonds in the reactive plasticizer of the present invention are incorporated into rubber, the type of double bonds is selected to some extent depending on the crosslinking system used. In the sulfur-accelerated systems commonly used in the rubber industry, the incorporation of double bonds in the main chain is a very important factor in terms of crosslinking efficiency. In the case of peroxide crosslinking, there is no problem even if a double bond is incorporated in the side chain.

<Examples> Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited thereto.

Example 1 (Production of Reactive Plasticizer-1) Polybutadiene glycol (average molecular weight:
600, average number of functional groups 2.2) (R-45 [T, Arco Inc. 1i1) 1000 g was charged and the temperature was raised to 80°C.

Next, in a nitrogen stream, 145 g of TDI was added dropwise at 80±5° C., and the mixture was aged until the NCO content did not decrease and the value reached equilibrium. Subsequently, n-butanol EO was added at 80±5°C in a nitrogen stream.
/PO (4.0 mol 15.3 mol) with knee ball 50■
B-100 (manufactured by Sanyo Chemical Industries, Ltd.) 451 g and 60 g of dibutyltin dilaurate were added, and the NCO content was 0.
It was confirmed that most of the hydroxyl groups of the polyene polyol were blocked as seen from the infrared absorption spectrum, and Reactive Plasticizer-1 was obtained.

Example 2 (Production of Reactive Plasticizer-2) In a pressurizable reaction vessel equipped with a temperature needle and a stirrer, 540 g of the same R-45HT as in Example 1 and 1 portion of caustic potash were added.
．． After adding 0g and sufficiently purging the inside of the reaction vessel with nitrogen,
12 O/PO=25/75 (wt/ut) mixture
After 200 g was injected under pressure at 0 to 130°C to complete the reaction, it was cooled to 70°C, 20g of activated clay was added and thoroughly stirred, the activated clay was filtered off, and 700g of the reaction product (II
) was obtained. This OH-V was 33.3.

Subsequently, in the same reaction vessel as in Example 1, 59 g and 10187 g of butyl cellosolve were reacted in the same manner as in Example 1.

Next, 1000 g of the reaction product (IT) and 50 μm of dibutyltin dilaurate were added to the mixture to obtain the desired reactive plasticizer-2.

Example 3 (Production of Reactive Plasticizer-3) The reaction product of Example 2 (■
) and 94 g of TDI were added, and the reaction was carried out in the same manner as in Example 1. Subsequently, 105 mol of n-butanol was added with Eupol LB-65 (manufactured by Sanyo Chemical Industries, Ltd.)
184g and 50μ of dibutyltin dilaurate were added, a blocking reaction was carried out, and the NCO content was determined.
From this, it was confirmed that the reaction was completed, and Reactive Plasticizer-3 was obtained.

Example 4 As shown in Table 1, rubber compositions of Experimental Examples 1 to 3 were prepared using raw rubber, various compounding agents, process oil (aromatic oil) as a plasticizer, and reactive plasticizer-1. . Various rubber characteristic values were measured for this rubber composition and are shown in Table 1.

Table 1 (Note 1) Measured according to JIS K-6300 (Note 2)
) Vulcanization conditions: 138°C x 30 minutes (Note 3) The vulcanized rubber sheet was pressed onto another oil-free rubber sheet, and after contacting at 70°C for 20 days, the degree of plasticizer migration was determined by acetone. It was measured by extraction rate.

As shown in Table 1, the reactive plasticizer-1 of the present invention (
The rubber compositions of Experimental Examples 2 and 3 in which the compound (obtained in Example 1) was blended had the following properties compared to the rubber composition of Experimental Example 1 in which aromatic oil was used as a plasticizer (or processing aid). The plasticizer extraction rate after vulcanization is low, and the acetone extraction rate of other rubber sheets after contact with other rubber sheets is also low.

In addition, 300% modella after acetone extraction and apparent T
The change in H is also low. Furthermore, it can be seen that the rubber composition of Experimental Example 3 in which 20 parts by weight of Reactive Plasticizer-1 was blended had a lower Mooney viscosity when unvulcanized and improved processability when unvulcanized.

Example 5 As shown in Table 2, rubber compositions of Experimental Examples 4 to 6 were prepared using raw rubber, various compounding agents, and dioctyl phthalate (DOP) as a plasticizer and reactive plasticizer-3. Regarding this rubber composition, various rubber characteristic values were measured and shown in Table 2.

Margin below this page Table 2 (Note 1) Measured according to JIS K-6300 (Note 2)
) Vulcanization conditions: Measured by extracting 2 g of rubber vulcanized at 153°C for 30 minutes with acetone (Note 3) Measured according to JIS K-6301 As shown in Table 2, reactive plasticizer-3 of the present invention ( The rubber compositions of Experimental Examples 5 and 6 using the material (obtained in Example 3) had a smaller amount of acetone extracted than Experimental Example 4 in which a large amount of the plasticizer DOP was blended.

Furthermore, since all of the blended DOP has been extracted in its entirety, the rubber compositions of Experimental Examples 5 and 6 contain reactive plasticizers.
It can be seen that a considerable amount of 3 remains. Also, 80℃
, the reduction rate of the low temperature embrittlement point after 60 days of heat aging was experimental example 5~
6 is significantly lower than Experimental Example 4.

Although the plasticizer DOP in the vulcanized rubber evaporates due to heat aging and the low-temperature embrittlement point increases, these results demonstrate that the reactive plasticizer-3 of the present invention does not volatilize and therefore does not increase the low-temperature embrittlement point. It shows. This shows that the reactive plasticizer-3 of the present invention has better low-temperature properties than DOP.

Example 6 As shown in Table 3, raw rubber, various compounding agents, aromatic process oil and reactive plasticizers 1 to 1 were used as plasticizers.
Rubber compositions of Experimental Examples 7 to 10 using No. 3 were prepared.

Various rubber property values were measured for this rubber composition and are shown in Table 3.

Margin below this page Table 3 (Note 1) - (Note 3) Vulcanization conditions of rubber used: 153℃ x 3
0 minutes (Note 2) Measured according to JIS K-6301 As shown in Table 3, the rubber compositions of Experimental Examples 8 to 10 containing reactive plasticizers 1 to 3 of the present invention were Compared to the rubber composition of Experimental Example 7 containing aromatic process oil, the amount of acetone extracted is small. Also, experimental examples 8 to 1
0 also has a low low temperature embrittlement point, and the low temperature embrittlement point changes only slightly even when extracted with acetone. On the other hand, in Experimental Example 7, most of the material was extracted by acetone, and the low temperature embrittlement point after extraction was increased. Looking at the change in hardness before and after acetone extraction, Experimental Example 7 shows a remarkable change in hardness, whereas Experimental Examples 8 to 1
0 shows almost no change in hardness, indicating that the plasticizing effect is maintained.

<Effect of the invention> The reactive plasticizer of the present invention has good compatibility with various rubbers.

That is, it is used for rubbers having double bonds as mentioned above, and also has the effect of greatly improving compatibility when blending these rubbers with other polar rubbers, resulting in new polymer blends. . Of course, it is also possible to use acrylic rubber, urethane rubber, silicone rubber, fluororubber, hydrin rubber, etc., which can be peroxide crosslinked even if they do not have double bonds.

Furthermore, compatibility and reactivity can be adjusted depending on the type of rubber and its intended use. For example, regarding the adjustment of reactivity, conventional methods add alkylene oxide to polyene glycol, and the reactivity can be adjusted by adjusting the amount of this addition.
It has the disadvantage that compatibility deteriorates due to the addition of alkylene oxide. However, even when alkylene oxide is added to the reactive plasticizer of the present invention, the terminals are blocked, so the compatibility is good without deterioration.

In addition to the above-mentioned effects, the reactive plasticizer of the present invention reduces the viscosity of unvulcanized rubber and improves processability when unvulcanized. Plasticized rubber that is mixed with rubber and then vulcanized reacts with polymers, reinforcing agents, etc. via the vulcanizing agent during vulcanization, so it is non-extractable with solvents and does not volatilize when heated. In other words, the reactive plasticizer of the present invention is very unlikely to migrate to other rubber parts, and does not change the properties of the rubber material in other parts (or change the physical properties of the plasticized part itself (for example, modulus). Furthermore, the reactive plasticizer of the present invention has excellent oil resistance due to less migration due to solvent extraction, and is less likely to cause contamination like conventional plasticizers.NBR The ability to improve low-temperature properties and maintain physical properties with little change over time, as seen in Tolyl Rubber), is a feature not found in conventional ester plasticizers.

Because it exhibits the above effects, the reactive plasticizer of the present invention can be used in general rubber products, as well as in tires, hoses, belts, packing, sealing materials, sealants, rubber mold products, rubber materials for civil engineering and construction, etc. Its use can be applied to a wide range of applications, such as medical materials and footwear.

Claims (1)

[Claims] 1. Polyene polyol-based NCO-terminated urethane prepolymer (a1) capped with a monofunctional active hydrogen-containing compound
, and a compound selected from the group consisting of polyene polyol (a2) end-capped with a monofunctional isocyanate (
A) A reactive plasticizer for rubber, characterized by comprising: