JPH07119045B2 - Mandrel - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a mandrel used in the manufacture of tubes or hoses.

[0002]

2. Description of the Related Art In the production of hoses and tubes, particularly in the case of hoses and tubes having a braid fiber reinforcement layer,
A round bar mandrel having an outer diameter matching the inner diameter of the inner pipe is used by being inserted into the inner pipe for the purpose of preventing the inner pipe from being deformed due to the external pressure during manufacturing.

Metals, rubbers, resins and the like are known as materials for such a mandrel, and among them, useful resin mandrels having flexibility are disclosed in, for example, Japanese Patent Application Laid-Open No. 61-61.
No. 2521, JP-A No. 61-135723, and the like. And, the most frequently used material is a nylon resin selected from the viewpoint of durability and cost.

By the way, a plasticizer is often used in the conventional nylon resin type mandrels in order to secure the flexibility thereof. However, it has been clarified that the plasticizer in such a mandrel is volatilized by repeated use of the mandrel or transferred to the inner tube of a hose or a tube, whereby the flexibility of the mandrel is rapidly lost.

The migration of the plasticizer is performed by the inner tube made of a polyamide resin having excellent properties such as mechanical strength, permeation resistance and chemical resistance, and liquids such as oil and gasoline, air, and Freon gas. It has been clarified that such a hose for transporting a gas or a pressure-resistant hose deteriorates the performance of the hose.

Further, the use of a plasticizer may cause the mandrel to become excessively flexible, causing problems during hose manufacture.

That is, when manufacturing a hose, an inner tube made of rubber or resin is applied on a mandrel, and if necessary, a reinforcing layer made of thread or metal steel wire and an outer tube made of rubber are applied, and then pressure is applied. When the rubber layer is vulcanized under heating, the mandrel may be unable to withstand the pressure due to the vulcanization and / or the pressure due to the heat shrinkage of the reinforcing layer and may be deformed.

On the other hand, in the case where the mandrel cannot secure flexibility, that is, when the mandrel is excessively rigid, when the mandrel is lengthened and wound up after the mandrel is manufactured, a large winding radius must be taken, and therefore the productivity is extremely high. bad.

Further, when a hose is manufactured by using such a rigid mandrel, the mandrel is linear because the repulsive force is strong when the inner tube is extruded onto the mandrel using an extruder for rubber or resin. Since it could not be pulled completely, excessive stress was generated in the crosshead portion of the extruder, and as a result, the wall thickness of the inner tube of the hose was not uniform, so-called uneven thickness was generated, and there was a problem in accuracy.

[0010]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned prior art, and is a nylon resin system having appropriate flexibility, heat resistance, dimensional stability, surface hardness and rigidity required for a mandrel. The purpose is to provide a flexible mandrel.

Further, from the viewpoint that the use of the plasticizer may be permitted depending on the use of the mandrel, the present invention provides the mandrel with appropriate flexibility, heat resistance, dimensional stability, surface hardness and rigidity. And a nylon resin-based mandrel containing a predetermined amount of a plasticizer.

[0012]

According to the present invention, 100 parts by weight of a nylon resin is added to 10 parts of an olefin elastomer.
The present invention provides a mandrel, which is obtained by extruding a resin composition containing 50 to 50 parts by weight into a rod shape.

Here, the resin composition is nylon resin 10
0 to 5 parts by weight of olefin elastomer 10 to 5
It preferably contains 0 parts by weight and 20 parts by weight or less of a plasticizer. Further, as the olefin-based elastomer, it is preferable to use an olefin-based elastomer modified with a carboxylic acid or an anhydrous acid.

The resin composition is preferably obtained by mixing a part of the nylon resin and a plasticizer to obtain plasticized nylon, and then melt-kneading the mixture with the rest of the nylon resin and the olefin elastomer. .

The present invention will be described in detail below. The nylon resin used in the present invention is not particularly limited as long as it is a nylon resin. As an example, nylon polymers such as nylon 6, nylon 11 and nylon 12, nylon 6,
66, nylon 6/10, nylon 6/12, and other nylon copolymers, and mixtures thereof.

Of these nylon resins, nylon 1
1, Nylon 12 and Nylon 6 · 12 are suitable for the present invention because they have flexibility, and especially Nylon 11
Is optimum because it has excellent heat resistance and heat distortion resistance.

It is also preferable to use nylon 11 in combination with another nylon resin, or to use a copolymer of nylon 11 in another polyamide.

The olefin elastomer used in the present invention may be any one as long as it has compatibility with the nylon resin.

As the monomer component constituting the olefin elastomer, ethylene, propylene, 1-butene, 1-pentene, 4-methylpentene-1,1-hexene, 1,4-hexadiene, dicyclopentadiene,
2,5-norbornadiene, 5-ethyl-2,5-norbornadiene, 5-ethylidene norbornene, 5- (1
'-Propenyl) -2-norbornene, isobutylene,
Examples thereof include butadiene, isoprene, vinyl acetate, styrene, vinyl chloride, ethyl acrylate, isobutyl acrylate, methyl methacrylate, zinc methacrylate, acrylamide, and the like. One or more of these may be olefin-based. It constitutes an elastomer.

The olefin elastomer also includes so-called modified products. That is, a carboxylic acid group,
An olefin elastomer having a functional group such as an acid anhydride group or an epoxy group in its side chain or main chain, or a compound having a functional group to this and an amine compound (ammonia, a primary or secondary aliphatic amine, olefin-based Heras Tomah like having functional groups such as shown in the following formula I~IV formed by addition reaction of cycloaliphatic amine is have an aromatic amine) in the side chain or main chain.

[0021]

[Chemical 1] (In the above formulas I to IV, R ¹ , R ² , R ³ , R ⁴ and R ⁵
Are each independently a hydrogen atom or an aliphatic, alicyclic or aromatic hydrocarbon acid group having 1 to 30 carbon atoms. )

Here, the carboxylic acid group, the acid anhydride group,
Used to introduce a functional group such as epoxy group olefinic Heras Tomah, beta-unsaturated carboxylic acid, and examples of its anhydride, an epoxy group-containing unsaturated compound,
Acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, crotonic acid, methylmaleic acid, methylfumaric acid, mesaconic acid, citraconic acid, glutaconic acid, methyl hydrogen maleate, ethyl hydrogen maleate, methyl hydrogen fumarate, itacone Methyl hydrogen acid, maleic anhydride, itaconic anhydride, citraconic anhydride, endobicyclo-
Examples include [2,2,1] -5-heptene-2,3-dicarboxylic anhydride, glycidyl acrylate, glycidyl methacrylate, vinyl glycidyl ether, and allyl glycidyl ether.

The amine compound used for forming the functional group represented by the above formulas I to IV by addition reaction with the compound having a functional group such as carboxylic acid group, acid anhydride group and epoxy group is Ammonia, methylamine, ethylamine, butylamine, hexylamine, dodecylamine,
Oleylamine, stearylamine, cyclohexylamine, benzylamine, aniline, naphthylamine, dimethylamine, diethylamine, methylethylamine,
Examples include dibutylamine, distearylamine, dicyclohexylamine, ethylcyclohexylamine, methylaniline, and phenylnaphthylamine.

Specific examples of the olefin elastomer include ethylene / propylene copolymer, ethylene / butene-1 copolymer, ethylene / propylene / 1,4-hexadiene copolymer, ethylene / propylene / 5-ethylidene norbornene. Copolymer, ethylene / propylene / 5
-Ethyl-2,5-norbornadiene copolymer, ethylene / propylene / dicyclopentadiene copolymer, and modified products obtained by introducing the above-mentioned functional groups into these.

The resin composition used in the mandrel of the present invention contains the above-mentioned nylon resin and olefin elastomer, and the ratio thereof is 10 to 50 parts by weight, preferably 10 parts by weight of olefin elastomer to 100 parts by weight of nylon resin. ~ 30 parts by weight. If the amount of the olefin-based elastomer is less than 10 parts by weight, the softening effect of the mandrel cannot be sufficiently obtained, and as described above, the mandrel productivity decreases due to the excessive winding radius, and the uneven distribution of the hose due to the excessive repulsive force. It occurs and is not preferable. On the other hand, if it is more than 50 parts by weight, the manufactured mandrel tends to be deformed due to the influence of pressure during vulcanization in the hose manufacturing process, shrinkage stress of the reinforcing layer, etc., which is not preferable.

The resin composition used in the mandrel of the present invention contains other components such as pigments, dyes, reinforcing agents, fillers, heat-resistant agents, etc., as long as the moldability and physical properties are not impaired.
Antioxidants, weathering agents, lubricants, crystal nucleating agents, antiblocking agents, antistatic agents, other polymers and the like may be contained.

The resin composition used in the mandrel of the present invention can be obtained by measuring the components contained therein, mixing and kneading.

The method is not particularly limited, and a generally known method can be adopted. However, after the nylon resin, olefin elastomer pellets, powder, and fine particles are uniformly mixed with a high-speed stirrer, they are sufficiently mixed. The most common method is melt-kneading with a single-screw or multi-screw extruder having kneading ability.

Further, since the compatibility between the nylon resin and the olefin elastomer is extremely good, a method of dry blending them at the time of molding without kneading with an extruder and molding by an extrusion method is also colorful. be able to.

The mandrel of the present invention can be obtained by extruding the resin composition for the mandrel into a rod shape.

In producing the mandrel of the present invention, conditions such as extrusion molding are not particularly limited, but one example is as follows.

That is, extrusion molding is carried out at 230 to 280 ° C.
The resin composition is extruded by an extruder in a certain degree to form a rod, which is extruded from a die and cooled while adjusting the size and the like in a cooling tank.

The mandrel of the present invention can prevent the deterioration of the performance due to the migration of the plasticizer from the mandrel during the production of the hose inner tube or the tube, and the increase of the mandrel hardness due to the decrease of the amount of the plasticizer in the mandrel. Is something
Although it can be used for manufacturing any hose or tube, it is particularly preferably used for manufacturing a fuel transportation hose, a low gas permeable hose, a pressure resistant hose, etc., in which the inner layer of the inner tube is formed of a polyamide resin To be

The resin composition for use in the mandrel of the present invention, the nylon resin, in addition to the olefinic Heras Tomah preferably also contains a plasticizer. The nylon resin and the olefin elastomer are as described above and will not be described again here.

The plasticizer used in the present invention is not particularly limited, but for example, Nn-butylbenzenesulfonamide, Nn-butylcyclohexanesulfonamide, N
Examples thereof include -t-butyl-2-benzothiazolyl sulfenamide, acetic acid-butylbenzenesulfonamide, and 2-ethylhexyl p-oxybenzoate.

The resin composition used for the mandrel of the present invention is 10 to 50 parts by weight, preferably 10 to 3 parts by weight of the olefinic elastomer based on 100 parts by weight of the nylon resin.
It contains 0 parts by weight and 20 parts by weight or less, preferably 15 parts by weight or less of a plasticizer.

The reason for limiting the amount ratio of the nylon resin to the olefin elastomer is as described above. Further, when the plasticizer is more than 20 parts by weight with respect to 100 parts by weight of the nylon resin, the manufactured mandrel becomes excessively soft, so that the pressure at the time of manufacturing the hose (vulcanization step) and the contraction of the reinforcing layer. It cannot withstand stress, and the mandrel size (outer diameter) changes significantly, which reduces the dimensional accuracy of the manufactured hose.

The resin composition used in the mandrel of the present invention may also contain other components such as pigments, dyes, reinforcing agents, fillers, heat-resistant agents and antioxidants within the range not impairing the gist of the present invention. , Weathering agents, lubricants, crystal nucleating agents, antiblocking agents, antistatic agents, and other polymers may be contained.

The method of kneading the blended components for obtaining the resin composition used in the mandrel of the present invention is not particularly limited and may be a general method. In particular, an unmodified copolymer as an olefin elastomer is used. In the case of using, a method is preferred in which a part of the nylon resin and a plasticizer are mixed to form a plasticized nylon, and then the remaining nylon resin and the olefin elastomer are melt-kneaded.

When kneading is carried out by such a method, the blended components are likely to be uniformly mixed.

The mandrel of the present invention can be used for the production of any hose or tube. When the amount of plasticizer is 15 parts by weight or less relative to 100 parts by weight of nylon resin, the inner layer of the inner tube is It is suitable for manufacturing a hose made of polyamide resin.

Further, the amount of the plasticizer is 100% nylon resin.
If more than 15 parts by weight and 20 parts by weight or less with respect to parts by weight,
It is preferable to use it for manufacturing a fuel transportation hose consisting of only a rubber inner tube, a general tube such as a pressure-resistant hose, and a hose whose characteristics such as permeability are not significantly affected by the migration of the plasticizer.

[0043]

EXAMPLES The present invention will be described in detail below with reference to examples.

(Example) A resin composition for mandrel whose composition is shown in Table A was obtained. The kneading of the blended components
Regarding Invention Examples 1 to 8 and Comparative Examples 1 to 5, a method of directly kneading a nylon resin, an olefin elastomer and, if necessary, a plasticizer at 220 ° C., and Invention Examples 9 to 1
Regarding No. 0, a part of the nylon resin and the plasticizer were kneaded to obtain plasticized nylon, and then the balance of the nylon resin and the olefin elastomer were added and the mixture was kneaded at 220 ° C.

These resin compositions were put in a 40 mm extruder and extruded at a temperature of 210 to 220 ° C. to 210 ° C.
It formed a rod-shaped flow in the die. Next, this rod-shaped material was extruded from a die and cooled while adjusting the size and the like in a cooling tank to form a round bar (mandrel) having an outer diameter of 11 mm.

With respect to the mandrel thus obtained, its flexibility and changes in flexibility due to heating were evaluated by the following method. Further, using the mandrel thus obtained and the mandrel after the heat cycle treatment, a hose is manufactured by the following method, the uneven thickness of the hose inner tube inner layer (resin layer) is molded, and the hose is manufactured as a whole. Later, the deformation of the mandrel itself was evaluated. The results are shown in Table A.

(Evaluation Method of Flexibility of Mandrel) Measurement of Flexibility The flexural modulus of the mandrel was measured using a commercially available flexural modulus tester to evaluate the flexibility. Further, the bending elastic modulus of the mandrel treated by the method was also measured in the same manner to evaluate the change in flexibility due to heating. The smaller the value of the bending elastic modulus, the higher the flexibility. Mandrel heat cycle treatment method Place the mandrel (30 cm in length) in a thermostatic chamber at 170 ° C.
For 5 hours and then at 40 ° C. for 7 hours. The heat cycle treatment with 1 cycle as this was carried out for 10 cycles for each mandrel.

(Manufacturing Method of Hose) Formation of Inner Layer of Hose Inner Tube (Resin Layer) On a mandrel which has been coated with a mold release agent and dried in advance, a resin extruder is used and a resin (nylon 11,
Toray Co., Ltd. BESNOTL is extruded to a thickness of 200
Form a resin layer of μm book layer. The conditions of the resin extruder are set by using flexible nylon resin (BESN manufactured by Toray Industries, Inc.).
OP40TL, containing 14% of N-n-butylbenzenesulfonamide which is a plasticizer), when the thin resin layer is formed, the deviation of the thickness (uneven thickness) is the smallest Set to. Formation of Inner Tube Outer Layer After applying an adhesive on the resin layer, the mandrel on which the resin layer is formed is passed through a rubber molding machine, and a butyl (IIR) rubber composition is extruded onto the resin layer to give a thickness of 1 Form a 0.8 mm inner tube outer layer. Formation of Reinforcing Layer A polyester system is braided using a braiding machine on the structurally unitized composite hose inner tube formed by and to form the reinforcing layer. Outer tube formation On the reinforcing layer, a chlorinated butyl (C
The l-IIR) type rubber composition is extruded to form an outer tube having a thickness of 2 mm. Vulcanization The outer tube of the molded hose is wrapped with a cloth in a tape shape, and then steam vulcanization is performed at a temperature of 150 ° C. and a pressure of 3.8 kg / cm ² for 60 minutes.

(Evaluation Method for Uneven Thickness of Inner Layer of Inner Tube of Hose) The evaluation mandrel was continuously passed through the crossbed of the resin extruder under the same conditions according to the method for producing the hose.
The maximum value of the uneven thickness of the resin layer formed on each mandrel was measured. The allowable maximum value of the uneven thickness of the thin resin layer is preferably within ± 10% of the set wall thickness (200 μm), that is, 40 μm or less.

(Method for evaluating deformation of mandrel) According to the method for manufacturing a hose described above, after laminating until vulcanization, cooling was carried out,
The mandrel was pulled out and observed for deformation of the mandrel. When unevenness due to contraction of the reinforcing layer was observed on the mandrel, and when it was not a perfect circle due to pressure deformation, it was determined to be deformed.

[0051]

[Table 1]

[0052]

[Table 2]

(Description of components in Table A) * 1) Toray Industries, Inc., unplasticized nylon 11 * 2) Toray Industries, Inc., nylon 11, plasticizer (Nn-butylbenzenesulfonamide) 14% Contained * 3) Mitsui Petrochemical Co., Ltd., maleic acid modified EP
M * 4) manufactured by BASF, Nn-butylbenzenesulfonamide * 5) manufactured by Yoshitomi Pharmaceutical Co., Ltd.

As is apparent from Table A, Invention Examples 1 to 4 (nylon resin + olefin elastomer) had excellent mandrel flexibility before the heat cycle treatment, that is, the original mandrel, and as a result, formed on those mandrels. The thickness deviation of the thin resin layer is within the target of 40 μm, which is good, and the flexural modulus increases even after the heat cycle treatment, but the change is small and still flexible. The uneven thickness of the thin resin layer formed on the mandrel after the heat cycle treatment is within 40 μm, and the characteristics are well maintained.

In Comparative Examples 1 and 2 having a low content of the olefin elastomer, the mandrel lacked in initial flexibility, the uneven thickness of the thin layer formed on the mandrel was extremely large from the beginning, and the mandrel was constantly used and was not heated. The rate of change in flexibility due to cycle processing is also large.

On the other hand, Comparative Example 3 containing more than 50 parts by weight (60 parts by weight) of the olefin elastomer has very good flexibility, and when the mandrel is used, the uneven thickness of the resin layer is small, but it is excessively flexible. Therefore, pressure applied during hose production (vulcanization) and stress strain due to contraction deformation of the reinforcing layer are inevitable, and unevenness occurs on the mandrel surface, and
Deformation of the cross-section also occurs and it is in constant use.

Inventive Examples 5 to 10 (nylon resin + olefin-based elastomer + plasticizer) also contained a small amount of plasticizer, and therefore were more flexible than those of Inventive Examples 1 to 4 (however,
It is so soft that the mandrel is not deformed during hose manufacturing. ). However, the change in flexural modulus due to heat cycle treatment is rather large.

Comparative Example 4 containing no olefin elastomer (nylon resin + plasticizer) was initially soft, but the flexural modulus increased remarkably by the heat cycle treatment, and it could not withstand repeated use. . It is considered that this is due to an increase in the crystallinity of the nylon resin (nylon 11) forming the mandrel and volatilization of the plasticizer.

When a mandrel is formed by adding an olefin elastomer to a nylon resin (nylon 11) and further adding a plasticizer, the amount of the plasticizer added is important.
Although the flexibility is further improved by adding the plasticizer, when the plasticizer is excessively added (Comparative Example 5), the mandrel is deformed during the production of the hose, which is not preferable.

Of the invention examples 5 to 10 containing the plasticizer, invention examples 9 and 10 were prepared by adding the plasticizer to nylon 1 in advance.
1 is mixed (14% of the total amount of nylon 11 and plasticizer)
Then, after that, a resin composition for a mandrel is prepared by melt-kneading a non-plastic type nylon resin and an olefin elastomer, but according to such a method,
Since the fine fraction becomes easy, the constituents can be mixed uniformly and quickly. And, as a result, a more flexible mandrel is obtained, and further, the mandrel is
It has excellent characteristics that the bending elastic modulus changes little by the heat cycle treatment and there is no deformation during the production of the hose.

[0061]

INDUSTRIAL APPLICABILITY According to the present invention, a nylon resin-based mandrel resin composition capable of imparting appropriate flexibility, heat resistance, dimensional stability, surface hardness and rigidity required for a mandrel, and a preferred resin composition thereof And a mandrel manufactured from the resin composition are provided.

The mandrel of the present invention can be used not only in the manufacture of general tubes or hoses, but also in the manufacture of fuel transportation hoses, low gas permeable hoses, pressure resistant hoses, etc. in which the inner layer of the inner tube is made of polyamide resin. Preferred, and therefore
The present invention allows such hoses to be manufactured easily and with consistent quality.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical display location B29L 23:00 (72) Inventor Takashi Masuda 1-82 Ikegamidai, Midori-ku, Nagoya-shi, Aichi (72) ) Hideto Takano 30-5 Motoshiro-cho, Fujinomiya-shi, Shizuoka (56) References JP-A 61-135723 (JP, A) JP-A 60-137962 (JP, A)

Claims (4)

[Claims] 1. A mandrel formed by extruding a resin composition containing 10 to 50 parts by weight of an olefin elastomer into a rod shape with respect to 100 parts by weight of a nylon resin. 2. A plasticizer is added to the nylon resin 10.
The mandrel according to claim 1, wherein a resin composition containing 20 parts by weight or less with respect to 0 parts by weight is used. 3. The mandrel according to claim 1, wherein the olefin elastomer is a carboxylic acid- or acid anhydride-modified olefin elastomer. 4. A resin composition prepared by mixing a part of a nylon resin and a plasticizer to obtain plasticized nylon, and then melt-kneading the mixture with the remaining nylon resin and olefin elastomer. Mandrel described in.