阅读说明：本技术 硫化橡胶用脱模剂 (Release agent for vulcanized rubber ) 是由 宗石彻也 木下裕贵 中岛顺市 于 2019-06-28 设计创作，主要内容包括：本发明提供一种可以同时发挥优异的脱模性和清洗性的硫化橡胶用脱模剂。所述硫化橡胶用脱模剂其特征在于,含有下述通式(1)所表示的聚胺氧化烯烃加成物以及下述通式(2)所表示的羧酸酰胺化合物。<Image he="110" wi="700" file="DDA0002111419880000011.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>[式(1)中,A<Sup>1</Sup>O和A<Sup>2</Sup>O分别独立地表示碳原子数为2～4的烯化氧基,a<Sup>1</Sup>和a<Sup>2</Sup>分别独立地表示1～40的数,b<Sup>1</Sup>和b<Sup>2</Sup>分别独立地表示1或2,c<Sup>1</Sup>和c<Sup>2</Sup>分别独立地表示0或1,b<Sup>1</Sup>、b<Sup>2</Sup>、c<Sup>1</Sup>和c<Sup>2</Sup>的合计为4,R<Sup>1</Sup>和R<Sup>2</Sup>分别独立地表示碳原子数为2～6的亚烷基,R<Sup>3</Sup>表示氢原子、碳原子数为1～3的烷基、或由碳原子数为2～4的烯化氧基构成的氧化烯烃链,d<Sup>1</Sup>表示0或1或2。]<Image he="358" wi="700" file="DDA0002111419880000012.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>[式(2)中,R<Sup>4</Sup>表示碳原子数为8～22的烃基,R<Sup>5</Sup>表示碳原子数为1～2的亚烷基,R<Sup>6</Sup>表示氢原子或甲基,X<Sup>1</Sup>表示-COOM、-SO<Sub>3</Sub>M或-PO<Sub>3</Sub>M所表示的阴离子性基团]。(The invention provides a release agent for vulcanized rubber, which can simultaneously exert excellent release property and cleaning property. The release agent for vulcanized rubber is characterized by containing a polyamine oxyalkylene adduct represented by the following general formula (1) and a carboxylic acid amide compound represented by the following general formula (2). [ in the formula (1), A 1 O and A 2 O independently represents an alkylene oxide group having 2 to 4 carbon atoms, a 1 And a 2 Each independently represents a number of 1 to 40, b 1 And b 2 Each independently represents 1 or 2, c 1 And c 2 Each independently represents 0 or 1, b 1 、b 2 、c 1 And c 2 Is 4, R in total 1 And R 2 Each independently represents an alkylene group having 2 to 6 carbon atoms, R 3 Represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or an oxyalkylene chain composed of an alkyleneoxy group having 2 to 4 carbon atoms, d 1 Represents 0 or 1 or 2.] [ in the formula (2), R 4 Represents a hydrocarbon group having 8 to 22 carbon atoms, R 5 Represents an alkylene group having 1 to 2 carbon atoms, R 6 Represents a hydrogen atom or a methyl group, X 1 represents-COOM, -SO 3 M or-PO 3 An anionic group represented by M]。)

1. A mold release agent for vulcanized rubber, wherein,

comprising a polyamine oxyalkylene adduct represented by the following general formula (1) and a carboxylic acid amide compound represented by the following general formula (2),

in the formula (1), A¹O and A²O independently represents an alkylene oxide group having 2 to 4 carbon atoms, a¹And a²Respectively is said alkylene oxide group A¹O and A²The average molar number of addition of O and each independently represents a number of 1 to 40, b¹And b²Each independently represents 1 or 2, c¹And c²Each independently represents 0 or 1, b¹、b²、c¹And c²Is 4, R in total¹And R²Each independently represents an alkylene group having 2 to 6 carbon atoms, R³Represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a group represented by the following general formula (11), d¹Represents 0 or 1 or 2, and is,

in the formula (11), A³O represents an alkylene oxide group having 2 to 4 carbon atoms, a³Is said alkylene oxide group A³The average molar number of O added is 1 to 40,

in the formula (2), R⁴Represents a hydrocarbon group having 8 to 22 carbon atoms, R⁵Represents an alkylene group having 1 to 2 carbon atoms, R⁶Represents a hydrogen atom or a methyl group, X¹Represents an anionic group represented by any one of the following general formulae (21) to (23),

-COOM…(21)

-SO₃M…(22)

-PO₃M…(23)

in the formulae (21) to (23), M independently represents a hydrogen atom or a monovalent cationic group.

2. A mold release agent for vulcanized rubber according to claim 1, wherein,

the content of the polyamine oxyalkylene adduct is 3 to 99.95% by mass, and the content of the carboxylic acid amide compound is 0.05 to 50% by mass.

3. The mold release agent for vulcanized rubber according to claim 1 or 2, wherein,

a in the general formula (1)¹O、A²O and A³O is each independently an ethyleneoxy group or a propyleneoxy group.

4. The mold release agent for vulcanized rubber according to claim 1 or 2, wherein,

r in the general formula (2)⁴Is an alkyl or alkenyl group having 8 to 18 carbon atoms.

Technical Field

The present invention relates to a release agent for vulcanized rubber.

Background

Rubber products such as rubber hoses are widely used as parts of various machines including automobiles. Many rubber products are formed by adding sulfur and a crosslinking agent to a raw material rubber such as natural rubber, ethylene-propylene-diene rubber, styrene-butadiene rubber, isoprene rubber, butadiene rubber, chloroprene rubber, butyl rubber, nitrile rubber, urethane rubber, silicone rubber, and fluororubber to vulcanize rubber molecules by crosslinking, and then extruding or molding a vulcanized rubber having elasticity and elasticity imparted to the raw material rubber. For example, a rubber hose is mainly manufactured by a method of inserting vulcanized rubber into a mold such as a core mold molded into a predetermined shape and pulling out the rubber hose after molding, or a method of inserting an unvulcanized raw rubber composition into the mold and vulcanizing and pulling out the rubber hose after molding.

In the molding of such rubber products, a mold release agent is used in order to facilitate the separation of the vulcanized rubber product after molding from the mold or the insertion of the raw rubber composition before molding into the mold, and examples of the mold release agent for the vulcanized rubber include polyalkylene glycols such as polypropylene glycol and polyethylene glycol, polyoxyalkylene glycols, fatty acid soaps, dimethyl silicone, modified silicone oils, and the like.

Furthermore, for example, Japanese patent application laid-open No. 2004-114472 (patent document 1) describes a mold release agent for vulcanized rubber containing a compound in which an ethyleneoxy group and a propyleneoxy group are randomly copolymerized in an aliphatic hydrocarbon group having 3 to 10 carbon atoms; japanese patent laid-open publication No. 2004-306409 (patent document 2) describes a core mold release agent for producing a hose, having a molecular weight of 2000 to 4000 and having the formula HO (EO)_a(PO)_b(EO)_cA polyoxyethylene-polyoxypropylene block copolymer represented by H, which contains an oxyethylene group (ethyleneoxy group, EO) in an amount of 20% or more and less than 40% of the total molecule as an active ingredient; japanese patent application laid-open No. 7-292236 (patent document 3) describes a combination of twoA mold release agent for vulcanized rubber comprising an amine alkylene oxide adduct in which ethylene oxide and propylene oxide are alternately bonded to each other.

Disclosure of Invention

Technical problem to be solved by the invention

However, the present inventors have found that: in the conventional release agent for vulcanized rubber, it is difficult to improve both the property (releasability) of facilitating the pulling-out operation of the molded vulcanized rubber product and the property (cleanability) of facilitating the removal of the release agent adhering to the surface of the molded vulcanized rubber product, and for example, the release agent described in patent document 1 has a problem of insufficient releasability although it can exhibit good cleanability. On the other hand, the present inventors have found that: the release agents described in patent documents 2 to 3 can exhibit a good release property to some extent, but have a problem that the cleaning property is insufficient, and particularly, the cleaning property is further lowered when the water temperature is high (for example, about 40 ℃).

The present invention has been made in view of the problems of the prior art, and an object thereof is to provide a release agent for vulcanized rubber which can exhibit both excellent releasability and excellent cleanability.

Means for solving the technical problem

The present inventors have conducted extensive studies to achieve the above object, and as a result, have found that the cleaning property of a release agent for vulcanized rubber is greatly improved by combining a carboxylic acid amide compound with an alkylene oxide adduct of polyamine having a specific structure. Further, it has been found that a release agent for vulcanized rubber, which comprises a combination of the alkylene oxide adduct of the polyamine and the carboxylic acid amide compound, has further improved releasability and can exhibit both excellent releasability and excellent cleanability, and the present invention has been completed.

That is, the release agent for vulcanized rubber of the present invention is as follows.

[1] A mold release agent for vulcanized rubber, which comprises a polyamine oxyalkylene adduct represented by the following general formula (1) and a carboxylic acid amide compound represented by the following general formula (2).

[ in the formula (1), A¹O and A²O independently represents an alkylene oxide group having 2 to 4 carbon atoms, a¹And a²Respectively is said alkylene oxide group A¹O and A²The average molar number of addition of O and each independently represents a number of 1 to 40, b¹And b²Each independently represents 1 or 2, c¹And c²Each independently represents 0 or 1, b¹、b²、c¹And c²Is 4, R in total¹And R²Each independently represents an alkylene group having 2 to 6 carbon atoms, R³Represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a group represented by the following general formula (11), d¹Represents 0 or 1 or 2.]

[ formula (11) wherein A³O represents an alkylene oxide group having 2 to 4 carbon atoms, a³Is said alkylene oxide group A³The average molar number of O added is 1 to 40.]

[ in the formula (2), R⁴Represents a hydrocarbon group having 8 to 22 carbon atoms, R⁵Represents an alkylene group having 1 to 2 carbon atoms, R⁶Represents a hydrogen atom or a methyl group, X¹Represents an anionic group represented by any one of the following general formulae (21) to (23)And (4) clustering.]

-COOM…(21)

-SO₃M…(22)

-PO₃M…(23)

In the formulas (21) to (23), M independently represents a hydrogen atom or a monovalent cationic group. ]

[2] The release agent for vulcanized rubber according to [1], wherein the content of the polyamine oxyalkylene adduct is 3 to 99.95% by mass, and the content of the carboxylic acid amide compound is 0.05 to 50% by mass.

[3]Such as [1]]Or [2]]The release agent for vulcanized rubber, wherein A in the general formula (1)¹O、A²O and A³O is each independently an ethyleneoxy group or a propyleneoxy group.

[4]Such as [1]]～[3]The release agent for vulcanized rubber as described in any one of the above, wherein R in the general formula (2)⁴Is an alkyl or alkenyl group having 8 to 18 carbon atoms.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, a mold release agent for vulcanized rubber can be provided which can exhibit both excellent mold release properties and excellent cleanability.

Detailed Description

Hereinafter, the present invention will be described in detail with reference to preferred embodiments.

The release agent for vulcanized rubber is characterized by containing a polyamine oxyalkylene adduct represented by the following general formula (1) and a carboxylic acid amide compound represented by the following general formula (2).

(polyamine oxyalkylene adduct)

In the present invention, the polyamine oxyalkylene adduct means that the polyamine has a primary amino group (-NH) having 2 or more groups bonded in substitution₂) The polyamine (2) has a structure in which an oxyalkylene chain is added to a hydrogen atom (active hydrogen) on a nitrogen atom of the polyamine. The polyamine oxyalkylene adduct of the present invention is represented by the following general formula (1).

[ in the formula (1), A¹O (wherein OA is used as¹) And A²O independently represents an alkylene oxide group having 2 to 4 carbon atoms, a¹And a²Respectively is said alkylene oxide group A¹O and A²The average molar number of addition of O and each independently represents a number of 1 to 40, b¹And b²Each independently represents 1 or 2, c¹And c²Each independently represents 0 or 1, b¹、b²、c¹And c²Is 4, R in total¹And R²Each independently represents an alkylene group having 2 to 6 carbon atoms, R³Represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a group represented by the following general formula (11), d¹Represents 0 or 1 or 2.]

[ formula (11) wherein A³O represents an alkylene oxide group having 2 to 4 carbon atoms, a³Is said alkylene oxide group A³The average molar number of O added is 1 to 40.]

In the general formula (1), A¹O and A²Alkylene oxide group represented by O, or R³A is a group represented by the general formula (11)¹O、A²O and A³The alkylene oxide groups represented by O may be the same or different from each other, and further, each of the alkylene oxide groups has a plurality of A¹O、A²O and A³Similarly, O may be the same or different. The alkylene oxide group is required to be an alkylene oxide group having 2 to 4 carbon atoms, that is, an ethyleneoxy group having 2 carbon atoms (hereinafter, occasionally referred to as "EO"), a propyleneoxy group having 3 carbon atoms (hereinafter, occasionally referred to as "PO"), or a butyleneoxy group having 4 carbon atoms (hereinafter, occasionally referred to as "BO"). The alkylene oxide group has more preferably 2 to 3 carbon atoms, that is, the alkylene oxide group is more preferably EO or PO. If the number of carbon atoms is within the above range, the releasability and cleanability of the release agent for vulcanized rubber become good.

The alkylene oxide chain (in- (AO) form obtained by addition of these alkylene oxide groups_aA group represented by-H) may be a chain formed by addition of 1 kind of the above alkylene oxide group alone, or a chain formed by co-addition of 2 or more kinds of the above alkylene oxide groups, and in the case of co-addition, block addition or random addition may be performed. Among these, from the viewpoints that dispersibility in water and adhesion to a mold are further improved and that the cleaning property of a mold release agent for a vulcanized rubber tends to be more excellent, the addition form of the alkylene oxide group is preferably a co-addition (random addition or block addition), and more preferably a co-addition of EO and PO. When the mode of addition of the alkylene oxide is a co-addition of EO and PO, block addition of EO after addition of PO is more preferable.

Further, when the oxyalkylene chain contains EO as an oxyalkylene group, the content of all EO in the general formula (1) is preferably 35% by mass or less, more preferably 3 to 30% by mass, based on the total oxyalkylene chain. If the content of all EO relative to all oxyalkylene chains exceeds the above upper limit, the mold release property and the cleaning property of the mold release agent for vulcanized rubber tend to be lowered.

In the general formula (1), a¹And a²Is represented by, or R³A is a group represented by the general formula (11)¹、a²And a³The average molar number of addition of the alkylene oxide groups per alkylene oxide chain may be the same or different from each other. The average number of moles of alkylene oxide added is 1 to 40, preferably 5 to 36, and more preferably 10 to 32. If the average molar number of addition of the alkylene oxide groups is less than the lower limit, the releasability of the release agent for vulcanized rubber tends to decrease, while if it exceeds the upper limit, the cleanability tends to decrease.

In the polyamine oxyalkylene adduct of the present invention, the polyamine has 2 or more primary amino groups (-NH)₂) In (2), the oxyalkylene chain may be added by substituting at least 1 of 2 hydrogen atoms (active hydrogen) respectively. Thus, the general formula(1) In (b)¹And b²Each independently represents 1 or 2, c¹And c²Each independently represents 0 or 1, b¹、b²、c¹And c²The total of (2) is 4. The polyamine oxyalkylene adduct of the present invention is more preferably b, from the viewpoint that the content of the above-mentioned alkylene oxide group can be further increased to further improve the releasability of the release agent for vulcanized rubber¹And b²Are both 2 and c¹And c²Are both 0.

In the general formula (1), R¹And R²Each independently represents an alkylene group having 2 to 6 carbon atoms. In the present invention, R is¹And R²From the viewpoint of further improving the releasability and cleanability of the release agent for vulcanized rubber, ethylene is particularly preferable.

In the general formula (1), R³Represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a group represented by the following general formula (11). A in the general formula (11)³O and a³As described above. In the present invention, from the viewpoint that the content of the alkylene oxide group can be further increased and the releasability of the release agent for vulcanized rubber tends to be further improved, R is³The group represented by the general formula (11) is preferable.

Furthermore, in the general formula (1), d¹Represents 0 or 1 or 2. In the present invention, d is defined as a releasing property of the releasing agent for vulcanized rubber and a cleanability thereof, from the viewpoint of further improving the releasability and the cleanability thereof¹Particularly preferably 0 or 1.

Such a polyamine oxyalkylene adduct can be obtained by, for example, using a polyamine (e.g., a polyalkylene polyamine such as an alkylenediamine or diethylenetriamine) as a raw material, substituting a hydrogen atom (active hydrogen) bonded to a nitrogen atom thereof, and addition-polymerizing the alkylene oxide group according to a conventional method. Alternatively, the polyamine may be obtained by using, as a raw material, a compound (e.g., N '-tetrakis (2-hydroxyalkyl) alkylenediamine, N', N ", N ″ -penta (2-hydroxyalkyl) dialkylenetriamine) to which a hydroxyalkylene group is added in place of an active hydrogen of the polyamine, and by addition-polymerizing the alkyleneoxy group in place of a hydrogen atom (active hydrogen) of the hydroxyl group.

As a method for addition polymerization of the alkylene oxide group, specifically, for example, a method in which a raw material such as the polyamine is charged into a pressure-resistant reactor, heated under an inert gas atmosphere, and a predetermined amount of alkylene oxide is introduced (pressed) to be added, and an alkali metal hydroxide or the like can be used as a reaction catalyst. Further, as a method for addition polymerization of the alkylene oxide group, there can be selected, depending on the desired addition mode of the alkylene oxide group: a method of introducing 1 kind of alkylene oxide in 1 stage and adding it, a method of introducing 2 or more kinds of alkylene oxides in 1 stage by mixing and adding them, a method of introducing 1 kind or 2 or more kinds of alkylene oxides in a plurality of stages and adding them, and the like.

(Carboxylic acid amide Compound)

In the present invention, the carboxylic acid amide compound is represented by the following general formula (2).

[ in the formula (2), R⁴Represents a hydrocarbon group having 8 to 22 carbon atoms, R⁵Represents an alkylene group having 1 to 2 carbon atoms, R⁶Represents a hydrogen atom or a methyl group, X¹Represents an anionic group represented by any one of the following general formulae (21) to (23).]

-COOM…(21)

-SO₃M…(22)

-PO₃M…(23)

In the formulas (21) to (23), M independently represents a hydrogen atom or a monovalent cationic group. ]

In the general formula (2), R⁴Represents a hydrocarbon group having 8 to 22 carbon atoms. From the viewpoint that the mold release property and the cleaning property of the mold release agent for vulcanized rubber tend to be further improved, the above-mentioned mold release agent is usedThe number of carbon atoms of the hydrocarbon group is preferably 8 to 18, more preferably 12 to 18. The hydrocarbon group may be saturated or unsaturated, and may be linear, branched or contain a cyclic structure, but is preferably a linear hydrocarbon group, and more preferably an alkyl group or an alkenyl group, from the viewpoint of further improving the releasability and cleanability of the release agent for a vulcanized rubber.

As such R⁴The hydrocarbon group having 8 to 22 carbon atoms is more specifically preferably an octyl group, a 2-ethylhexyl group, a decyl group, a lauryl group, a myristyl group, a palmityl group, a stearyl group, an oleyl group, or a behenyl group, and is further preferably a lauryl group, a myristyl group, a palmityl group, a stearyl group, or an oleyl group.

In the general formula (2), R⁵Represents an alkylene group having 1 to 2 carbon atoms. In the general formula (2), R⁶Represents a hydrogen atom or a methyl group, preferably a methyl group.

In the general formula (2), X¹Represents an anionic group represented by any one of the following general formulae (21) to (23).

-COOM…(21)

-SO₃M…(22)

-PO₃M…(23)

In the general formulae (21) to (23), M independently represents a hydrogen atom or a monovalent cationic group.

The monovalent cation group is not particularly limited as long as it can be neutralized by forming a salt with the anion of the general formulae (21) to (23), and examples thereof include alkali metals (Li, Na, K, Rb, Cs) and ammonium (NH)₄) Alkanolamines (monoalkanolamines, dialkanolamines, trialkanolamines, and the like; preferably an alkanolamine having 1 to 4 carbon atoms). In the general formulae (21) to (23), M is preferably independently a hydrogen atom, an alkali metal or ammonium, from the viewpoint of availability and the like. In the present invention, the anionic group may be an acidic group from which a hydrogen atom or the cationic group is removed, and the degree of neutralization is not particularly limited and may be appropriately adjusted.

In the present invention, X is¹From the viewpoint of further improving the releasability and cleanability of the release agent for vulcanized rubber, the anionic group represented by the general formula (21) or (22) is particularly preferable.

More specific examples of such carboxylic acid amide compounds include N-acyl sarcosines such as N-lauroyl sarcosine, N-myristoyl sarcosine, N-palmitoyl sarcosine, N-stearoyl sarcosine and N-oleoyl sarcosine; N-acyl-N-methyltaurines such as N-lauroyl methyltaurine, N-myristoyl methyltaurine, N-palmitoyl methyltaurine, N-stearoyl methyltaurine and N-oleoyl methyltaurine may be 1 kind of these alone or 2 or more kinds of these in combination. Among these, the carboxylic acid amide compound is preferably at least 1 selected from N-acyl sarcosines and N-acyl-N-methyltaurines, and more preferably at least 1 selected from N-acyl sarcosines, from the viewpoint that the mold release properties and the cleaning properties of the release agent for vulcanized rubber tend to be further improved.

(Release agent for vulcanized rubber)

The release agent for vulcanized rubber of the present invention contains the polyamine oxyalkylene adduct and the carboxylic acid amide compound. The polyamine oxyalkylene adduct and the carboxylic acid amide compound may be contained in an amount of 1 species, respectively, or in combination of 2 or more species.

In the release agent for vulcanized rubber of the present invention, the content of the polyamine oxyalkylene adduct (the total content thereof in the case of 2 or more species, the same applies hereinafter) is preferably 3 to 99.95% by mass, more preferably 5 to 99.90% by mass, and still more preferably 10 to 99.85% by mass, based on the total mass of the release agent for vulcanized rubber. When the content of the polyamine oxyalkylene adduct exceeds the upper limit, although the releasability is improved, the cleanability tends to be lowered; on the other hand, if the amount is less than the lower limit, the releasability tends to be low although the cleanability is improved.

In the release agent for vulcanized rubber of the present invention, the content of the carboxylic acid amide compound (the total content of 2 or more of them, the same applies hereinafter) is preferably 0.05 to 50% by mass, more preferably 0.10 to 30% by mass, and still more preferably 0.15 to 20% by mass, based on the total mass of the release agent for vulcanized rubber. Even if the content of the carboxylic acid amide compound exceeds the upper limit, improvement of the mold release property and the cleaning property cannot be expected much, and therefore, the economical efficiency tends to deteriorate; on the other hand, if the amount is less than the lower limit, the releasability and cleanability tend to be lowered.

In the release agent for vulcanized rubber of the present invention, the mass ratio of the content of the polyamine oxyalkylene adduct to the content of the carboxylic acid amide compound is preferably 75:25 to 99.95:0.05, more preferably 80:20 to 99.90:0.10, and still more preferably 83:17 to 99.85: 0.15. Even if the content of the carboxylic acid amide compound exceeds the upper limit of the content of the polyamine oxyalkylene adduct, the improvement of the releasability and the cleaning property cannot be expected much, and therefore the economical efficiency tends to deteriorate; on the other hand, if the amount is less than the lower limit, the releasability and cleanability tend to be lowered.

The release agent for vulcanized rubber of the present invention may further contain water. The release agent for vulcanized rubber of the present invention can be used after being diluted with water as needed at the time of use, as described below. The water is not particularly limited, and examples thereof include purified water, sterilized water, natural water, and a mixture thereof.

The release agent for vulcanized rubber of the present invention may further contain other components in addition to the polyamine oxyalkylene adduct and the carboxylic acid amide compound, within a range not impairing the effects of the present invention.

Examples of the other components include: surfactants such as soaps; silicones such as dimethyl silicone and modified silicone oil; rust inhibitors such as benzotriazole and benzothiazole; mineral oil; the vegetable oil or the conventionally known release agent component may be 1 kind of the above, or may be a combination of 2 or more kinds. In the present invention, when the release agent for vulcanized rubber further contains the other components, the content thereof (the total content thereof in the case of 2 or more species, the same applies hereinafter) is preferably 50 parts by mass or less based on 100 parts by mass of the total of the content of the polyamine oxyalkylene adduct and the content of the carboxylic acid amide compound.

In the present invention, a mixture of the polyamine oxyalkylene adduct and the carboxylic acid amide compound may be used as it is as the release agent for vulcanized rubber of the present invention, or the mixture may be further mixed with the water and, if necessary, the other components to be used as the release agent for vulcanized rubber of the present invention. The mixing method is not particularly limited.

The release agent for vulcanized rubber of the present invention may be diluted with water to a low concentration at the time of use as necessary, and used as a release agent solution. The release agent for vulcanized rubber of the present invention is easily dissolved in water and has excellent adhesion to a mold, and therefore, even at a low concentration, excellent releasability and cleanability can be exhibited at the same time. The total content of the polyamine oxyalkylene adduct and the carboxylic acid amide compound in the release agent solution is not particularly limited, and is suitably adjusted depending on the method of use, and is preferably 3 to 100% by mass, more preferably 5 to 80% by mass, and still more preferably 10 to 50% by mass.

The release agent for vulcanized rubber of the present invention can be prepared, for example, by a method of previously applying the above release agent solution to a portion of a mold which is in contact with vulcanized rubber or unvulcanized rubber; a method of applying the above mold release agent solution to the end of an unvulcanized rubber hose; and a combination of these methods. The release agent for vulcanized rubber of the present invention can exhibit both excellent releasability and cleanability even when mixed with a component exuded from rubber during vulcanization, and therefore, can be applied to a method of inserting a vulcanized rubber into a mold and pulling it out after molding, or a method of inserting an unvulcanized raw rubber composition into the mold and pulling it out after vulcanization and molding.

The mold is not particularly limited in shape, and the release agent for vulcanized rubber of the present invention can be suitably used as a release agent for a core mold used for molding a vulcanized rubber hose. The coating method is not particularly limited, and conventionally known methods can be used, and examples thereof include a method of spraying with a spray gun (spray coating) and a method of coating with a brush. The amount of coating can be appropriately adjusted depending on the concentration of the above-mentioned mold release agent solution, the type and insertion speed of the vulcanized rubber or unvulcanized rubber, the temperature of the mold, and the like.

The vulcanized rubber is not particularly limited, and examples thereof include vulcanized rubbers obtained by vulcanizing natural rubber, ethylene propylene diene rubber, styrene butadiene rubber, isoprene rubber, butadiene rubber, chloroprene rubber, butyl rubber, nitrile rubber, urethane rubber, silicone rubber, fluororubber, and the like. The release agent for vulcanized rubber of the present invention can be suitably used for vulcanized rubber obtained by vulcanizing ethylene propylene diene monomer, for example.