JPH0655405B2 - Mandrel for hose manufacturing - Google Patents

Description

TECHNICAL FIELD The present invention relates to a mandrel for manufacturing a hose which is excellent in dimensional stability, durability, heat resistance, mold release property and flexibility in long-term use. More specifically, it relates to a mandrel for producing a hose having the above-mentioned characteristics, which is composed of a composition mainly composed of a specific 4-methyl-1-pentene / α-olefin random copolymer.

[Conventional technology]

Rubber hoses such as water hoses, steam hoses, and air hoses are usually [I] a mandrel having the same diameter as the diameter of the intended product rubber hose, and unvulcanized raw rubber is melt-coated or the mandrel is not yet covered. A step of manufacturing an unvulcanized rubber hose by winding a vulcanized rubber sheet, [II] a step of coating lead on the unvulcanized rubber hose integrated with the mandrel of [I], [III] A step of winding the unvulcanized rubber hose coated with a mandrel, [IV] a step of vulcanizing the wound unvulcanized rubber hose in a vulcanizing device such as a vulcanization kiln, [V] after completion of vulcanization , The step of stripping off the lead coating on the rubber hose, [VI] Flowing a pressurized gas or fluid between the mandrel and the rubber hose to separate the mandrel and the rubber hose, and remove the mandrel. Process, has been by go-between production to be passing through the. In this case, the mandrel used as the core material of the rubber hose must have flexibility so that it can be easily wound up, and has sufficient heat resistance to withstand the high temperature in the vulcanization process. Must be Further, when the rubber hose is separated, it is required that the rubber hose is easily peeled off and that the peeled surface is also clean and that it has an excellent releasing property. Further, in addition to satisfying the above-mentioned requirements, the dimensional stability must be such that shrinkage or elongation does not occur and the caliber dimension is not disturbed, and the durability must be such that it can be repeatedly used any number of times. However, the conventionally used nylon mandrels have inadequate flexibility, and when used repeatedly several times, they cause elongation and shrinkage, which causes problems in dimensional stability and mechanical strength. Also deteriorates and the durability is poor,
There was a problem that it could be used only two or three times at most. As a mandrel improved on such a drawback, a mandrel mainly composed of poly-4-methyl-1-pentene is disclosed in Japanese Utility Model Publication No. 60-18903 and JP-A No. 60-1831.
Proposed in No. 6 bulletin, etc. However, the mandrel made of only poly (4-methyl-1-pentene) homopolymer described in such publication is not flexible, and particularly in molding a hose having a large diameter, the mandrel coated with unvulcanized rubber is wound up. However, even if a low molecular weight plasticizer is added to impart flexibility, such a low molecular weight compound is liable to volatilize at high temperatures during the rubber vulcanization process, etc. It has been found that the dimensions may change during use). The former is 4-methyl-1-
An embodiment using a copolymer containing at least 60% by weight of pentene is also described, but when the copolymerization component is increased, the rigidity or softening point is usually rapidly lowered, or the low molecular weight substance is increased, which is not always necessary. It cannot be said to be suitable as a mandrel, and in any case, the performance was insufficient as a hose manufacturing mandrel.

[Problems to be solved by the invention]

In view of such a situation, the present inventor further studied variously in order to develop a hose manufacturing mandrel excellent in dimensional stability, durability, heat resistance, mold release property and flexibility in long-term use, and a specific melting point, 4-methyl-1-having crystallinity and the like
It has been found that a mandrel produced from a composition mainly composed of a penten / α-olefin random copolymer achieves the above object, and has completed the present invention.

[Means for solving problems]

That is, the present invention has a 4-methyl-1-pentene content of
40 to 80 mol%, melting point 140 to 220 ° C, softening point
Crystallinity by 90-190 ℃ and X-ray is 15-35%
4-methyl-1-pentene and α- having 3 to 7 carbon atoms (excluding 4-methyl-1-pentene)
Dimension for long-term use, characterized in that it consists of a composition of 100 to 20% by weight of a random copolymer (A) with olefin and 0 to 80% by weight of poly-4-methyl-1-pentene (B). It is intended to provide a mandrel for hose production which is excellent in stability, durability, heat resistance, mold release property and flexibility.

[Work]

The 4-methyl-1-pentene / α-olefin random copolymer (A) used in the present invention (hereinafter sometimes abbreviated as random copolymer (A)) means that the content of 4-methyl-1-pentene is 40 to 80 mol%, preferably 50 to 75 mol%,
Melting point 140 to 220 ° C, preferably 160 to 210
℃, softening point 90 to 190 ℃, preferably 110 to 1
4-Methyl-1-pentene having a crystallinity of 15 to 35%, preferably 20 to 30% at 80 ° C. and X-rays and having 3 to 7 carbon atoms (excluding 4-methyl-1-pentene) ), Which is a random copolymer with α-olefin, and has an intrinsic viscosity [η] in a decalin solvent of 135 ° C. of 0.5 to 6 dl / g, preferably 1 to 5 dl / g.

A copolymer having a 4-methyl-1-pentene content of less than 40 mol% has low heat resistance and mechanical strength, whereas a copolymer having a 4-methyl-1-pentene content of more than 80 mol% has poor flexibility. The 4-methyl-1-pentene content in the present invention is a value measured by the ¹³ C-NMR method.

A copolymer having a melting point of less than 140 ° C has poor heat resistance. The melting point in the present invention is 10 using a differential scanning calorimeter (DSC) and a press sheet having a thickness of 0.1 mm 20 hours after molding.
Take a sample of mmg, 0-250 at a heating rate of 10 ℃ / min.
Measure the heating curve up to ℃, the maximum endothermic peak is the melting point (Tm)
And

A copolymer having a softening point of less than 90 ° C has poor heat resistance. The softening point in the present invention is measured by using a thermal mechanical analyzer (TMA), and the thickness after the lapse of 20 hours after molding is 1.0 mm.
1cm square sample is taken from the press sheet of and the diameter is 0.025
Apply an inch needle to one side of the sample and load 49 g to 10 ℃
The temperature was measured when the needle penetrated to a depth of 0.1 mm by heating at a heating rate of / min, and the temperature was taken as the softening point.

A copolymer having a crystallinity of less than 15% by X-ray has low rigidity and mechanical strength, while a copolymer having a crystallinity of more than 35% has poor flexibility. The crystallinity in the present invention is determined by taking a 2 × 4 cm sample from a 1.0 mm thick pressed sheet 20 hours after molding and measuring an X-ray diffraction curve by an X-ray diffraction method to obtain a reflection angle of 2
θ: 4 to 30 ° was used as a baseline, and the crystal part and the amorphous part were separated, the area was measured, and then the crystal part was determined as the weight%.

In each press sheet, the random copolymer (A) was put into a mold with a thickness of 0.1 and 1.0 mm, respectively, in a predetermined amount, preheated for 5 minutes with a hydraulic press molding machine heated to 240 ° C, and then pressed for 5 minutes. The mold was immediately transferred to a cooling press molding machine cooled with water at 20 ° C., and cooling was performed for 5 minutes.

Α having 3 to 7 carbon atoms which is copolymerized with 4-methyl-1-pentene in the random copolymer (A) used in the present invention.
Specific examples of olefins include propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, and among these α-olefins, 1-butene and 1-hexane are preferred. Especially, 1-hexane is preferable because it has an excellent balance between flexibility and rigidity. A copolymer with ethylene has low rigidity, while a copolymer with 8 or more carbon atoms, for example, a copolymer with 1-decene or 1-hexadecene has a low softening point, low rigidity, and low mechanical strength. The object of the present invention cannot be achieved.

In addition to the above characteristics, the random copolymer (A) used in the present invention has a soluble content in an acetone / n-decane mixed solvent (volume ratio 1/1) at 10 ° C. of 4 × [η] ^−0.8 % by weight. Below, 0.2 × [η] ^{−0.8 to} 3.8 × [η] ^−0.8 % by weight
([Η] is the numerical value of the intrinsic viscosity of the random copolymer (A), which is the value excluding the units), is the value of bleeding of the low molecular weight polymerized component on the surface when processed into a film or the like. It is preferable because it does not cause stickiness due to out and is excellent in mold releasability and dimensional stability. The soluble content of the copolymer in the mixed solvent in the present invention is measured and determined by the following method. That is, in a 150 ml flask equipped with a stirring blade, 1 g of the copolymer sample, 0.05 g of 2,6-di-tert-butyl-4
-Methylphenol, add 50 ml of n-decane, 120 ℃
Dissolve in oil bath. After dissolution, the mixture is allowed to cool naturally at room temperature for 30 minutes, then 50 ml of acetone is added for 30 seconds, and the mixture is allowed to cool on a water bath at 10 ° C for 60 minutes. A solution in which the precipitated copolymer and low molecular weight polymer component are dissolved is separated by filtration with a glass filter,
The solution was dried at 10 mmHg at 150 ° C. until a constant weight was obtained, the weight was measured, and the soluble content of the copolymer in the mixed solvent was calculated and determined as a percentage with respect to the weight of the sample copolymer. In the measuring method, stirring was continuously performed from the time of dissolution until immediately before filtration.

Random copolymer used in the present invention (A) melting point, softening point,
Acetone / n-decane mixed solvent soluble components, etc. are 4-methyl-
It is not uniquely determined by the content of 1-pentene, but depends on the polymerization conditions, and a copolymer having properties outside the scope of the present invention has heat resistance, rigidity, flexibility, and the like. The balance is poor.

The 4-methyl-1-pentene / α-olefin random copolymer (A) having various properties as described above is, for example, (a) a magnesium compound, a titanium compound, a diester and optionally a halogen compound (magnesium compound). Or a highly active titanium catalyst component containing magnesium, titanium, a halogen and a diester as an essential component, which is formed by reacting each other) when the titanium compound contains a halogen atom). In the presence of a catalyst formed from an aluminum compound catalyst component and (c) an organosilicon compound catalyst component having a Si-O-C bond, 4-methyl-1-pentene is added at a temperature of about 20 to about 200 ° C. It is obtained by copolymerizing with α-olefin having 3 to 7 carbon atoms such as propylene, 1-butene and 1-hexene. As described above, the copolymerization conditions and the like for producing the random copolymer (A) suitable for use in the present invention are described in detail in Japanese Patent Application No. 60-216258 filed by the present applicant.

The poly-4-methyl-1-pentene (B) used in the present invention means 4-methyl-1-pentene homopolymer or 4-methyl-1-pentene.
Methyl-1-pentene and other α-olefins such as ethylene, propylene, 1-butene, 1-hexene, 1-
A copolymer of octene, 1-decene, 1-tetradecene, 1-octadecene and the like with α-olefin having 2 to 20 carbon atoms, usually 4-methyl-1-pentene containing 85 mol% or more of 4-methyl-1-pentene. It is a polymer mainly composed of pentene. The melt flow rate (MFR, load: 5 kg, temperature: 260 ° C.) of poly-4-methyl-1-pentene (B) is preferably in the range of 0.5 to 200 g / 10 min. M
When the FR is less than 0.5 g / 10 min, the melt viscosity is high and the moldability is poor, and when the FR is over 200 g / 10 min, the melt viscosity is low and the moldability is poor, and the mechanical strength is low.

The manufacturing mandrel for a hose of the present invention is the 4-methyl-
1-Pentene / α-olefin random copolymer (A) 10
0 to 20% by weight, preferably 95 to 30% by weight and the poly-4-methyl-1-pentene (B) 0 to 80% by weight,
It is preferably composed of 5 to 70% by weight of the composition. The hose manufacturing mandrel of the present invention may be composed of the random copolymer (A) alone, but the poly-4-methyl-1-pentene is used to adjust the rigidity of the mandrel.
(B) may be added up to 80% by weight, preferably in the range of 5 to 70% by weight, relative to 100% by weight of the composition. When the amount of poly-4-methyl-1-pentene (B) exceeds 80% by weight, the flexibility is lowered and it cannot be used for a mandrel for manufacturing a hose having a large diameter.

In order to obtain a composition of the random copolymer (A) and the poly-4-methyl-1-pentene (B), both are prepared by various known methods within the above range, for example, V-blender, ribbon blender, Hensyl L mixer. , A method of mixing with a tumbler blender, or a method of granulating with an extruder after mixing with the blender, a method of melt kneading with a single-screw extruder, a multi-screw extruder, a kneader, a Banbury mixer, etc., and a method of granulating or pulverizing, etc. Can be taken. Further, in the composition, various compounding agents which are usually used by adding to polyolefin, such as weather resistance stabilizers, heat resistance stabilizers, lubricants, pigments, dyes, nucleating agents, inorganic fillers, etc., within the range not impairing the object of the present invention. It may be added in.

The mandrel for manufacturing a hose of the present invention can be easily manufactured by a usual thermoplastic resin extrusion molding method. The shape of the mandrel depends on the shape of the desired hose, but is generally pipe-shaped or rod-shaped.
In addition, a reinforcing wire, a piano wire, a rope made of fibers such as polyester thread, cotton thread, or the like may be incorporated as a core wire in the mandrel.

〔The invention's effect〕

The mandrel for producing a hose, which is composed of the composition mainly composed of the 4-methyl-1-pentene / α-olefin random copolymer (A) of the present invention, is not only the conventional nylon mandrel but also poly-4-methyl. A mandrel composed of a composition obtained by adding a low molecular weight plasticizer to poly-4-methyl-1-pentene, which is superior in flexibility, releasability, and dimensional stability to a mandrel mainly containing -1-pentene. Since it has excellent dimensional stability, durability, heat resistance, and releasability in long-term use, it can be used as a mandrel for resin hose and rubber hose production for a long time.

〔Example〕

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples as long as the gist thereof is not exceeded.

Example 1 [Production of 4-methyl-1-pentene / 1-hexene random copolymer] <Preparation of titanium catalyst component (a)> 4.76 g (50 mmol) of anhydrous magnesium chloride, 25 ml of decane and 23.4 ml of 2-ethylhexyl alcohol. (150mmol)
Was heated at 130 ° C for 2 hours to form a uniform solution, then 1.11 g (7.5 mmol) of phthalic anhydride was added to this solution, and the mixture was stirred and mixed at 130 ° C for an additional 1 hour to form phthalic anhydride. Dissolve in the homogeneous solution. The homogeneous solution thus obtained is cooled to room temperature and then added dropwise to 200 ml (1.8 mmol) of titanium tetrachloride kept at -20 ° C over 1 hour. After the completion of charging, the temperature of this mixed solution was raised to 110 ° C over 4 hours, and when it reached 110 ° C, 2.68 ml (12.5 mmol) of diisobutyl phthalate was added, and the mixture was kept at the same temperature for 2 hours with stirring. To do. After completion of the reaction for 2 hours, a solid part was collected by hot filtration, and this solid part was mixed with 200 ml of TiCl ₄
After resuspending at, heat reaction is further performed at 110 ° C for 2 hours. After the reaction was completed, the solid part was collected again by hot filtration.
Wash thoroughly with 10 ° C decane and hexane until no free titanium compound is detected in the washing solution. The titanium catalyst component (a) prepared by the above production method was stored as a hexane slurry, and a part of this was dried for the purpose of examining the contact composition. Titanium catalyst component thus obtained
The composition of (a) is 3.1% by weight titanium, 56.0% by weight chlorine, 17.0% by weight magnesium and 2% diisobutyl phthalate.
It was 0.9% by weight.

<Polymerization> Into a 200 SUS reaction kettle, 20 1-hexene, 60 4-methyl-1-pentene (hereinafter abbreviated as 4MP) per hour, 80 mmol triethylaluminum, 80 mmol trimethylmethoxysilane, titanium atom Converted to 1.2 mm
The titanium catalyst component (a) of ol was continuously charged. The hydrogen partial pressure in the gas phase was kept at 1.5 kg / cm ² and the polymerization temperature was kept at 70.

The polymerization liquid was continuously withdrawn so that the amount of liquid in the reaction vessel became 100, the polymerization was stopped with a small amount of methanol, and unreacted monomers were removed to obtain 7.5 kg of a copolymer per hour.
4-Methyl-1-pentene.1 thus obtained
-Excene random copolymer (hereinafter abbreviated as PMH-I)
Has a 4MP content of 55 mol%, a melting point of 168 ° C, and a softening point of
140 ° C, crystallinity 24%, intrinsic viscosity [η] is 2.2 dl /
The content of g and acetone.n-decane-soluble component was 1.7% by weight.

[Production of Composition and Press Sheet]

Poly 4-methyl-1-pentene [1-hexadecene / 1
-Octadecene (weight ratio 50/50) content 6 mol%, MF
R: 26 g / 10 min, hereinafter abbreviated as PMP-1] 50% by weight
And PMH-I obtained by the above method (however, as a stabilizer, PH-I
MH-I: tetrakis [methylene-based on 100 parts by weight
3 (3,5-di-tert-butyl-4-hydroxyphenol) propionate] methane 0.15 part by weight, dilauryl thiodipropionate 0.25 part by weight, zinc stearate 0.
03 parts by weight were added. ) 50% by weight was mixed with a Henschel mixer and then melt-kneaded with a 40 mmφ extruder (set temperature 260 ° C.) to obtain a composition I. Then, using this composition I, at a temperature of 250 ° C. and a pressure of 5 minutes for 1 mm thickness and 2 by a press molding machine.
A sheet with a thickness of mm was formed. Using this sheet, a test was conducted by the following method.

Initial elastic modulus (kg / cm) (FM): ASTM D 638, 1 mm thick press sheet Bleed-out property (BL): 1 mm thick press sheet was left in an oven at 50 ° C for 48 hours and then judged by touch.

○: No sticky or slimy feeling ×: Sticky or slimy feeling Tensile elongation at break (%) (EL): ASTM D 638, 2 mm thick press sheet Heat loss (% by weight): 160 The press sheet was left in a hot air circulation type oven at ℃ for 48 hours and the weight change was judged.

Durability: A 2mm thick pressed sheet is sandwiched between sheets of unvulcanized rubber of the following composition, and the rubber is vulcanized at 160 ° C for 30 minutes.

After the completion of vulcanization, the sheet was taken out, the rubber was peeled off, and the releasability from the press sheet was measured. This operation was repeated 10 times with the same press sheet, and the following measurements were performed at the 4th and 10th times.

(Unvulcanized rubber sheet composition) Ethylene / propylene / terpolymer 100 parts Paraffin oil 100 parts Carbon 150 parts Defoamer 5 parts Zinc white 5 parts Stearic acid 1 part Vulcanization accelerator 2.5 parts Sulfur yellow 0.5 parts Dimensional stability (%) (L): Shrinkage rate of a 2 mm thick press sheet Appearance: Visual releasability: Feeling at the time of peeling from a vulcanized rubber sheet was judged by touch and visually.

◯: Peeling off neatly without resistance △: Difficult to peel off due to a little resistance ×: Not peeling off neatly due to adhesion Table 1 shows the results.

[Mandrel and hose manufacturing]

After melting Composition-I in a 65 mmφ extruder (molding temperature: 240 ° C), a 13.7 mmφ cylindrical die for molding a mandrel (molding temperature: 230
13.5 mmφ mandrel-I was manufactured by a method in which the molten rod-shaped molten resin was extruded and introduced into a cooling water tank equipped with a 13.6 mmφ sizing device for cooling. Then, using Mandrel-I, the unvulcanized rubber compound was plasticized at 100 ° C. in a 65 mmφ extruder and extrusion-coated on Mandrel-I to a thickness of 5 mm, and a tape made of canvas was wound on it. Next, the rubber layer was vulcanized by heating with steam at 160 ° C. for 40 minutes.

After cooling, the mandrel-I was pulled out to produce a vulcanized rubber hose. After manufacturing the hose using the same mandrel-I three times, the appearance of the mandrel-I was evaluated by the following methods.

Change in outer shape (%): Increase rate of outer diameter of mandrel (%) Appearance: Visual releasability: Judgment was made by resistance when the mandrel was manually pulled out from a vulcanized rubber hose having a length of 0.5 m.

○: Can be pulled out without resistance.

△: There is some resistance and it is difficult to extract.

The results are shown in Table 1.

Example 2 Example 1 was repeated except that PMP-1 was 70% by weight and PMH-I was 30% by weight. The results are shown in Table 1.

Example 3 Instead of PMP-1 used in Example 1, the charge amount of 1-hexane and 4MP was changed, and the hydrogen partial pressure was appropriately changed to obtain 4MP content of 70 mol. %,
Melting point 195 ° C, softening point 165 ° C, crystallinity 26%, intrinsic viscosity [η] 2.5 dl / g and acetone / n-decane-soluble component 2.
The same procedure as in Example 1 was carried out except that 0% by weight of 4-methyl-1-pentene / 1-hexene random copolymer (hereinafter abbreviated as PMH-II) was used. The results are shown in Table 1.

Example 4 Example 4 was repeated except that the PMH-II used in Example 3 was used alone. The results are shown in Table 1.

Comparative Example 1 Same as Example 1 except that 90 parts by weight of PMP-1 and 10 parts by weight of α-olefin oligomer (trade name: Ripolube Lion Co., Ltd. average molecular weight 568) were used in place of PMH-I. I went to. The results are shown in Table 1.

Comparative Example 2 The procedure of Example 1 was repeated except that PMP-1 was used alone in Comparative Example 1. The results are shown in Table 1.

Comparative Example 3 Nylon 6 (Toray Industries, Inc.) was used instead of the composition-I of Example 1.
The same procedure as in Example 1 was repeated except that Toray nylon resin Amira CM1021) manufactured by Toray was used. The results are shown in Table 1.

Comparative Example 4 [Production of Random Copolymer] Into 200 SUS reaction kettles, 20 1-hexane per hour, 60 4-methyl-1-pentene (hereinafter abbreviated as 4MP), 40 mmol diethylaluminum chloride, titanium 20 mmol of titanium trichloride in terms of atoms was continuously charged, the hydrogen partial pressure in the gas phase was kept at 1.5 kg / cm ² , and the polymerization temperature was kept at 70 ° C.

The polymerization liquid was continuously withdrawn so that the amount of liquid in the reaction vessel was 100, the polymerization was stopped with a small amount of methanol, and unreacted monomers were removed to obtain 0.8 kg of copolymer per hour. It was

4-Methyl-1-pentene.1 thus obtained
-Hexene random copolymer (hereinafter abbreviated as PMH-III) has a 4MP content of 64 mol%, a melting point of 190 ° C, a softening point of 165 ° C, a crystallinity of 25% and an intrinsic viscosity [η] of 2.2 dl / g.
And acetone-n-decane-soluble content was 2.8% by weight.

[Evaluation]

Example 1 was repeated except that PMH-III was used instead of PMH-I. The results are shown in Table 1.

Claims (1)

[Claims] 1. The content of 4-methyl-1-pentene in the range of 40 to 80 mol%, the melting point of 140 to 220 ° C., the softening point of 90 to 190 ° C. and the crystallinity by X-ray of 15 to 35%. Some 4-methyl-1-pentene and 3 to 7 carbon atoms
Composition of 100 to 20% by weight of a random copolymer (A) with α-olefin (excluding 4-methyl-1-pentene) and 0 to 80% by weight of poly-4-methyl-1-pentene (B) A mandrel for manufacturing a hose, which is characterized in that it is made of a material.