JP4298589B2 - Nonwoven fabric for protecting inner and outer surfaces of pipes - Google Patents

Description

  The present invention relates to a nonwoven fabric for a protective layer used to form a protective layer on the inner surface and / or outer surface of a tube such as a reinforced plastic composite tube.

  Recently, reinforced plastic composite pipes have become popular because they are lighter than metal pipes and concrete pipes and have excellent workability, and are also used as a means of transporting various fluids because of their light weight and excellent corrosion resistance and strength. ing.

These conventionally used reinforced plastic composite pipes are provided, for example, with an intermediate layer made of resin mortar between an inner layer and an outer layer made of fiber reinforcement, and partly between the inner layer and the intermediate layer and between the outer layer and the intermediate layer. A structure reinforced with a fiber chopping material inserted therein (see, for example, Patent Document 1), a structure in which a coating layer made of a nonwoven fabric and a thermosetting resin is provided on the outer peripheral side of a synthetic resin pipe material (see, for example, Patent Document 2), or friction In order to reduce resistance, a structure in which a protective layer made of a resin mixed with carbon powder is laminated on the inner peripheral surface of the fiber reinforced resin layer on the inner and outer peripheral surfaces of the reinforced plastic composite tube (see, for example, Patent Document 3) is known. Yes.
JP-A-6-155596 JP-A-8-25506 Japanese Patent Laid-Open No. 11-129363

  However, each of the above conventional structures is useful and improved as a reinforced plastic tube, respectively, but has difficulty in workability, and particularly forms a coating layer made of a nonwoven fabric and a thermosetting resin. However, the non-woven fabric has poor strength and elongation characteristics and has a problem in use over time. Further, when the non-woven fabric becomes rough, the impregnation of the impregnated resin also deteriorates and pilling is difficult.

  The present invention addresses the actual situation as described above, and in particular provides a non-woven fabric suitable for the protective construction of the inner and outer surfaces of a reinforced plastic pipe, thereby giving uniformity to the inner and outer surfaces of the protective layer, excellent corrosion resistance, and little secular change. The object is to easily form a protective layer on the inner and outer surfaces of the tube.

That is, the non-woven fabric for the inner and outer surface protective layers of the pipe of the present invention that meets the above-mentioned purpose is a sheet-shaped non-woven fabric having a basis weight of 10 to 50 g / m ² and a thickness of 50 to 150 μm consisting of a high melting point fiber and a heat-fusible conjugate fiber. A non-woven fabric having a 5% stretch stress in the range of 40 N / 5 cm to 80 N / 5 cm, a breaking elongation of 10 to 25%, and an air permeability of 150 to 400 cc / cm ² / sec. It is.

  In particular, in the above nonwoven fabric, the high melting point fiber is a high melting point polyester fiber, the heat fusible conjugate fiber is composed of a high melting point polyester resin and a low melting point polyester resin, and the mixing ratio of the high melting point fiber and the heat fusible conjugate fiber is high. Nonwoven fabrics in the range of 50/50 to 5/95 are preferred.

  The heat-fusible conjugate fiber used for the nonwoven fabric is a core-sheath type or side-by-side type fiber, and the melting point of the low melting point component is preferably in the range of 90 ° C to 180 ° C.

  The non-woven fabric of the present invention is, for example, a die surface in a Drostholm-type molding apparatus in which a cylindrical mold is connected so as to rotate around a rotation axis extending in a horizontal direction from the apparatus main body. A nonwoven fabric is impregnated and wound around the inner and outer surfaces of the tubular reinforced plastic supplied to the substrate, and the resin is cured between 110 ° C. and 160 ° C. to form a protective layer.

  When the protective nonwoven fabric of the present invention is used for the protective layer on the inner and outer surfaces of the tube, the stress is 40 N / 5 cm to 80 N / 5 cm when stretched 5%. Therefore, the nonwoven fabric is impregnated with resin, or the tube is wound as a protective layer. It does not easily stretch and deform when attached, and the workability is good, the quality is not inferior, and the breaking elongation and air permeability are within the required ranges, so the nonwoven fabric breaks. The generation of fiber pieces due to the above is prevented, the impregnation property during resin impregnation is improved, and a remarkable effect is expected on the workability and quality protection in forming the protective layer on the inner and outer surfaces of the reinforced plastic pipe as a whole.

  Hereinafter, specific embodiments of the present invention will be described in detail.

The present invention is a sheet-like nonwoven fabric having a basis weight of 10 to 50 g / m ² and a thickness of 50 to 150 μm, comprising a high melting point fiber and a heat-fusible composite fiber as described above, and a 5% elongation stress of 40 N / 5 cm to 80 N. / 5 cm, the elongation at break is in the range of 10 to 25%, and the air permeability is in the range of 150 to 400 cc / cm ² / sec.

  Specifically, a general-purpose high-melting polyester fiber having a melting point of 260 to 270 ° C. is used as the high-melting fiber, and a high-melting polyester resin and a melting point range of 90 to 180 ° C. are used as the heat-fusible fiber. A core-sheath type or side-by-side type composite fiber made of a low-melting polyester resin is used, and these fibers are usually used in a mixed fiber ratio of 50/50 to 5/95.

  Here, if the melting point of the low melting point component of the heat-sealing fiber is less than 90 ° C., it is not preferable because it cannot cope with the treatment temperature for curing the resin to be impregnated thereafter, usually the unsaturated polyester resin.

  In addition, if the mixing ratio of the high-melting fiber and the heat-fusible fiber is out of the above range and the ratio of the heat-fusible fiber is less than 50%, the bonding between the single fibers becomes insufficient and fluff is generated. Since it becomes easy, it is not preferable.

  On the other hand, if the heat-fusible fiber exceeds 95%, the uniformity of the nonwoven fabric is inferior. Therefore, it is preferable that 5% or more of the high-melting fiber serving as the core is mixed.

  In the above case, the fineness of the high melting point fiber and the heat-fusible fiber constituting the nonwoven fabric should be 5.0 decitex or less as the fineness, and the high melting point fiber if the combination of finenesses is 5.0 decitex or less. May be large or the heat-fusible fiber may be large. However, if the fineness exceeds 5.0 dtex, the fibers constituting the nonwoven fabric become thick, the nonwoven fabric has poor strength and elongation properties, and the nonwoven fabric becomes rough, so the degree of resin impregnated is preferred. Absent.

  And in forming a nonwoven fabric by mixing the high melting point fiber and the heat-fusible fiber, for example, after uniformly opening the high-melting point polyester short fiber and the heat-fusible composite short fiber, carding is performed, A uniform web is prepared, and then the protective nonwoven fabric of the present invention is obtained by passing through a pair of heating rollers in which the upper roller is made of an iron heating roller and the lower roller is made of a heat-resistant rubber roller.

  In this case, the processing temperature is preferably 100 to 200 ° C. If it is less than 100 ° C., the adhesion of the heat-fusible fiber becomes insufficient, and if it exceeds 200 ° C., the properties of the high melting point fiber will be affected. Neither is desirable because it may become non-uniform.

  Further, the treatment speed is preferably in the range of 1 m / min to 10 m / min, and if it is less than 1 m / min, the productivity is inferior and the fusion between fibers by the treatment becomes insufficient. Is effective.

In particular, the pressure at the time of the treatment is not so much a problem, but usually 10 kgf / cm ^{2 to} 50 kgf / cm ² is preferable.

  Since this processing pressure is related to speed and temperature, the above range is preferable from the viewpoint of production stability.

  Thus, as described above, the nonwoven fabric obtained as described above is used as the nonwoven fabric for the protective layer of the present invention by imparting the following characteristics.

  That is, as a characteristic of the nonwoven fabric for protective layer, first, the first is the range of stress at the time of 5% elongation of the nonwoven fabric, and the range of 40 N / 5 cm to 80 N / 5 cm is preferable.

  When the stress at 5% elongation of the nonwoven fabric is less than 40 N / 5 cm, the nonwoven fabric easily stretches and deforms due to processing load in the process of impregnating the nonwoven fabric with resin or winding it around a tube as a protective layer, resulting in poor processing, quality Is not preferable because it becomes inferior.

  Further, if the stress at the time of 5% elongation of the nonwoven fabric exceeds 80 N / 5 cm, the nonwoven fabric itself is hard, the resin impregnation property is inferior, and it is not preferable because it becomes film-like and wound around the tube.

  Next, the second is the breaking elongation of the nonwoven fabric, and this range is preferably in the range of 10% to 25%. If the breaking elongation is less than 10%, fiber fragments are generated when the nonwoven fabric breaks, which is not preferable. .

  This is because the heat-fusible fiber is strongly fused to the fiber and is shattered when broken. Further, if the elongation is 25% or more, there is a problem that the nonwoven fabric is stretched and difficult to break when it is subjected to a tensile breakage treatment.

The third is the permeability of the nonwoven fabric, the air permeability of the nonwoven fabric is ^{150cc / cm 2 / sec~400cc / cm} 2 / sec range are preferred.

An air permeability of less than 150 cc / cm ² / sec is not preferable because the resin does not penetrate well and impregnates poorly. On the other hand, if the air permeability exceeds 400 cc / cm ² / sec, the resin impregnation amount is large and it is difficult to adjust the impregnation amount, which is not preferable.

  Hereinafter, specific embodiments of the nonwoven fabric of the present invention will be described in detail.

Example 1
30% by mass of polyester short fibers having a fineness of 2.2 decitex and a fiber length of 51 mm, and a polyester / low melting point polyester composite having a fineness of 1.45 dtex and a fiber length of 51 mm (melting point of core-sheath type composite fiber, low melting point polyester: 110 ° C. ) Uniform mixing of 70% by mass of short fibers (weight per unit area: about 25 g / m ² ), carding to create a uniform web, and a pair of heating rolls (upper iron heating temperature 160 ° C., The lower roll rubber roll non-heated) was subjected to an interfiber bonding treatment at a treatment speed of 5 m / min and a pressure between rolls of 20 kgf / cm ² to obtain a nonwoven fabric for protective layer of the present invention.
Example 2
Similar to Example 1, carding is performed with the same structure fineness, low melting point of composite short fiber, mixed fiber ratio, basis weight, and a uniform web is formed, and a pair of heating rolls (upper iron heating temperature 140 is continuously formed). ° C., to obtain a processing speed 3m / min, protective layer nonwoven fabric of the present invention to inter-fiber bonding process with inter-roll pressure 20 kgf / cm ² under a roll rubber roll unheated).

Example 3
30% by mass polyester short fiber with a fineness of 2.2 decitex and a fiber length of 51 mm, and a polyester / low melting point polyester composite with a fineness of 2.2 decitex and a fiber length of 51 mm (core-sheath type composite fiber, melting point of low melting point polyester: 150 ° C.) short 70% by mass of fibers are uniformly mixed (appropriate mass is about 25 g / m ² ), carded to create a uniform web, and a pair of heating rolls (upper roll iron heating temperature 175 ° C., lower roll Non-heated) was subjected to inter-fiber adhesion treatment at a treatment speed of 5 m / min and a pressure between rolls of 20 kgf / cm ² to obtain a nonwoven fabric for protective layer of the present invention.

Comparative Example 1
50% by mass of a polyester short fiber having a fineness of 1.45 dtex and a fiber length of 51 mm, and a polyester / low melting point polyester composite having a fineness of 1.45 dtex and a fiber length of 51 mm (melting point of core-sheath type composite fiber, low melting point polyester: 125 ° C.) 50% by mass of short fibers are uniformly mixed (weight per unit area: about 25 g / m ² ), and then a carding process is performed to form a uniform web. A pair of heating rolls (upper roll iron heating temperature 190 ° C., lower roll) A non-heated rubber roll) was subjected to an interfiber bonding treatment at a treatment speed of 5 m / min and a pressure between rolls of 20 kgf / cm ² to obtain a nonwoven fabric for a comparative protective layer.

Comparative Example 2
50% by mass of polyester short fiber having a fineness of 2.2 decitex and a fiber length of 51 mm and 50% by mass of polyester unstretched yarn having a fineness of 4.4 decitex and a fiber length of 56 mm were uniformly mixed (weight per unit area: about 25 g / m ² ). Next, carding is performed to form a uniform web, and a pair of heating rolls (upper roll iron heating temperature 185 ° C., lower roll rubber roll non-heated) is processed at a processing speed of 5 m / min and an inter-roll pressure of 20 kgf / cm ² . Interfiber bonding treatment was performed to obtain a nonwoven fabric for comparative protective layer.

Comparative Example 3
Polyester / low melting point polyester composite (core-sheath type composite fiber, melting point of low melting point polyester: 110 ° C.) short with a fineness of 2.2 decitex, 30% polyester short fiber with a fiber length of 51 mm, and a fineness of 1.45 dtex with a fiber length of 51 mm 70% by mass of fibers are uniformly mixed (mass weight about 25 kgf / cm ² ), then carded to create a uniform web, and a pair of heating rolls (upper iron heating temperature 140 ° C., The non-heated lower roll was subjected to an interfiber bonding treatment at a treatment speed of 5 m / min and a pressure between rolls of 20 kgf / cm ² to obtain a nonwoven fabric for a comparative protective layer.

  For the above Examples 1 and 2 and Comparative Examples 1 to 3, the basis weight, thickness, 5% elongation stress, breaking elongation, and air permeability were measured, and a protective layer was formed on the inner and outer surfaces of the tube together with the unsaturated polyester resin. The processability and pilling properties (resin impregnation properties) when forming sapphire were compared. The results were as shown in Table 1.

  In the table, the basis weight, thickness, 5% elongation stress, breaking elongation, and air permeability were measured, and the dry heat shrinkage was measured according to the following methods (a) to (f).

Further, the workability and pilling property were evaluated according to the following criteria (a) and (b), respectively.
(a) Weight per unit area It was determined in accordance with the method described in 8.4.2 of JIS L1096.
(b) Thickness It was measured at a load of 2 KPa according to the method described in JIS L1096, 8.5.1.
(c) Stress at 5% elongation (N / 5cm)
N = 3 samples of 5 cm × 30 cm are taken in the vertical direction.

Tensilon manufactured by Toyo Bold-In Co., Ltd. is used, and the average value is expressed as the stress at the time of 5% elongation of the stress strain curve at a gripping interval of 20 cm and a pulling speed of 20 cm / min.
(d) Elongation at break (%)
N = 3 samples of 5 cm × 30 cm are taken in the vertical direction.

Tensilon manufactured by Toyo Bald Inn Co., Ltd. is used, and the elongation at break is expressed as an average value at a gripping interval of 20 cm and a pulling speed of 20 cm / min.
(e) Air permeability (cc / cm ² / sec)
Kato Tech Air Permeability Tester average of n = 3
(I) Pilling (resin impregnation)
10 g of polybest curing agent is added to 100 g of unsaturated polyester resin (polybest main ingredient) (Sunday Paint Co., Ltd.) for FRP, and stirred well to prepare a uniform solution.

    The above solution is applied to the sample and cured. The state of the sample after curing is determined.

The sample surface is uniform and free of spots. ○
The sample surface is rough but there are no spots. △
The sample surface is uneven and uneven. ×
(B) Workability When the sample is torn at both ends, the sample does not stretch at break and no fiber powder is produced. ○
The sample stretches slightly when it breaks. △
Fiber powder is generated when the sample breaks. ×

Claims (3)

It is a sheet-like non-woven fabric having a basis weight of 10 to 50 g / m ² and a thickness of 50 to 15 μm, comprising a high melting point fiber and a heat-fusible composite fiber, and the non-woven fabric has a 5% elongation stress of 40 N / 5 cm to 80 N / 5 cm. A non-woven fabric for a protective layer for inner and outer surfaces of a tube, characterized by being in a range, having a breaking elongation of 10 to 25% and an air permeability of 150 to 400 cc / cm ² / sec.   The high-melting point fiber is a high-melting point polyester fiber, the heat-fusible conjugate fiber is composed of a high-melting point polyester resin and a low-melting point polyester resin, and the mixture ratio of the high-melting point fiber and the heat-fusible conjugate fiber is 50 / 50-5. The nonwoven fabric for inner and outer surface protective layers of a pipe according to claim 1, which is in the range of / 95.   The nonwoven fabric for inner and outer surface protective layers of a pipe according to claim 1 or 2, wherein the heat-fusible conjugate fiber is a core-sheath type or side-by-side type fiber, and the melting point of the low melting point component is in the range of 90 ° C to 180 ° C.