JPS59201850A - Thermal recoverable article - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to heat recoverable articles, and more particularly to heat recoverable articles having dimensional recoverability against heat and uses thereof.

A recoverable article is an article that undergoes a substantial change in its dimensional shape when subjected to a heat treatment. Typically, these items are
The term "heat recoverable" as used herein also includes articles that, upon heating, recover to their original shape before being deformed, or adopt a new shape even if they have not been previously deformed.

In its most common form, such articles are disclosed in, for example, U.S. Pat.
No. 3.957.372, the heat-shrinkable sleeve is made of a polymeric material exhibiting elastic or plastic properties. The analogy is U.S. Patent No. 2,
As clarified in No. 027.962, the initial dimensionally heat-labile shape may be continuously modified, such as expanding an extruded tube while hot into a dimensionally heat-labile shape. In other cases, a preformed dimensionally heat-stable article is transformed into a dimensionally heat-stable shape in another process. .

The polymeric material may be crosslinked. One method of making heat recoverable articles is to form the polymeric material into the desired heat-stable shape and then crosslink the polymeric material to form the article with either a single crystalline melting point, depending on the type of polymer, or a polymer with a crystalline melting point for amorphous materials. The process consists of heating the article to a temperature above its softening point, deforming the article, and then cooling it in that state to maintain the deformed state of the article. In use, the article in the deformed state is thermally unstable and will tend to assume its initial thermally stable shape upon application of heat. Other methods include deforming a substantially uncrosslinked polymer at a temperature below the crystalline melting or softening point of the material and combining one or more material articles and at least one polymeric component into at least one hollow heat recovery. The process consists of crosslinking the substantially uncrosslinked material after forming the shape of the sexual article.

In other articles, such as those described in GB 1440524, an elastic member is held in elongation by a second member such that upon heating the second member weakens and the first elastic member recovers. I can do it.

It has been found that heat recoverable articles have particular use in the perimeter protection of elongate substrates, such as telecommunications cables.

In such applications, the heat-shrinkable article is placed around the object to be wrapped and then restored by heating its outer surface with a gas torch, such as a propane torch.

U.S. Patent No. 3,669,157 (Caro
lina Narrow Fabric Compan
y) B Yohi Japanese Patent Specification Special Sho 53-13805 (
It is proposed to provide a heat-shrinkable tubular knitted article that can be filled with certain heat-setting resins. However, the inventors have discovered that once the heat-shrinkable knitted fabric of such an article is heat-recovered, the heat-recoverable fibers tend to break down under its own recovery force. They are very difficult to install with open flames from flares or similar heating devices such as hot air guns.

The present invention includes heat-recoverable knitted fabrics comprising fibers that recover in size after heating and have a tensile strength at the recovery temperature of at least Q, l M Pa, some of the knitted fabrics having a thickness of at least 0.03 m. a substrate comprising an outer surface coated with a layer of polymeric material, preferably a stress-free polymeric material, in part the polymeric material being flexible without flowing when heated to enable thermal recovery of the article; A dimensionally heat recoverable article for at least a portion of the packaging is provided.

"Recovery temperature" of a polymeric heat recovery material means the temperature at which recovery of the polymeric material is substantially complete. Generally, the recovery temperature is defined as the crystalline melt transition temperature - the polymer if the polymer is crystalline. ; +il (If it is a fixed form, it is the glass transition temperature.

The polymeric material formed in the outer layer is softened at a temperature below the recovery temperature to allow recovery of the fibers - while the polymeric material would otherwise flow or flow out of the article upon heating and melt. Shouldn't.

The layer of polymeric material is preferably crosslinked from a treated thermoplastic polymer, either chemically crosslinked to render it non-fusible, or crosslinked by radiation treatment. The polymeric material has a complex dynamic viscosity at the recovery temperature of the fiber to allow it to flow or not fall during recovery.
isocity) of less than 10 poise, more preferably at least 10 poise, most preferably at least 10 poise, but preferably at the recovery temperature of the fiber.
more than 9 - more preferably more than 108 - especially 10
Preferably it does not exceed 7 whiz. Dynamic complex modulus (c
complex dynamic, but values significantly higher than lO9 poise may prevent the article from recovery. Dynamic complex viscosity - for example Van Wager - Lyon
By Kim and Cowell: Viscosi
ty and flow measurement No. 6
Chapter-1 (Leaderman, 2 Viscoe
Lasticity and its measurement
element Rheology Volume 12 Chapter 1 and by F. S. Locketc: Non-] 1n
Viscoelastic Sol 1ces Chapter 1 (Academic press). The layer of polymeric material is preferably made from a thermoplastic polymer that has been cross-linked, either chemically or by radiation cross-linking, to render it non-fusible.

The article of the invention enables advantageous properties such as good mechanical strength of textiles for use in heat-shrinkable articles on the one hand, and on the other hand for application in gas flame implements or other previously proposed articles. It has the advantage of allowing recovery even when using harsh heating tools. The ability of such a flame torch to recover heat-shrinkable articles can be measured in terms of torch index: The flame rate is constant constant flame velocity (Lor
d↓, the amount of time it takes to substantially damage the fabric or other heat-shrinkable article used in the present invention by overheating. This is the ratio to the time taken. Therefore, the higher the value of Flame Rate, the more likely it is that an item can be healed by a flame weapon, whereas the lower the value of Flame Rate, the more the item can be healed by a flame weapon. It is less suitable for recovery. In fact, if the flame rate is less than 2, it is essentially impossible to recover with flame tools. Articles with high flame rates may also find utility in applications such as high 11[lambda] environments and other harsh heating methods.

The inventors have discovered that although knitted fabrics made from heat-recoverable fibers exhibit relatively low flame rates, by laminating the knitted fabrics in accordance with the present invention, the flame rate of the recoverable knitted fabrics is substantially reduced. We have found that it is possible to increase the rate.

If the layer of polymeric material were to act merely as a thermal barrier, the time to damage the article due to overheating and the time to recover would be expected to increase at respective rates, and therefore the flame rate would remain constant. Therefore, it is difficult to fully understand the reason for the increased flame rate of articles according to the present invention. Most surprisingly, however, many articles according to the present invention are found to exhibit higher flame rates than conventional heat-shrinkable N-1 products.

In general, the flame rate of fJt+j woven composite structures was found to increase as the thickness of the polymer layer increases. The thickness of the polymeric material layer is - preferably at least 0.05 mm - more preferably at least 0.05 mm.
07 mm - especially at least 0.1 mm, more specific deviations of at least 1.5 mm, most specific deviations of at least 0.2 mm. In practice, the maximum layer thickness is 2 mm
- preferably 1# - most preferably 0.6 mm.

If this layer has a thickness substantially greater than 2TnJn, there is a risk that the outer layer will burn out before the So15 fabric reaches its recovery temperature.

The layer of polymeric material can be made from a wide variety of polymers, provided that it is softened after heating and that recovery of the fabric often occurs. In order to facilitate recovery of the fibers - the polymeric material - preferably fiber itf:
Recovery/111. 1', the softening point is not less than 20°C, more preferably the recovery temperature of the fiber itself is less than 41λ degrees, and the recovery temperature is at least 10'
It has a softening point of C. Preferably, however, this softening point should be no lower than 40°C below the recovery temperature of the fiber.

Examples of thermoplastic polymers that can be used to form such layers include ethylene/
Vinyl acetate copolymers - ethylene/acrylic ethyl copolymers, linear low-density polyethylenes including low-density and high-density grades - polyphelenes - polybutylene - polyesters - polyamides - polyetheramides , perfluoroethylene/ethylene copolymer---polyvinyritine fluoride. Considering additional classes of these materials, this includes acrylic elastomers and copolymers thereof, including acrylonitrile butadiene styrene bronze copolymers, acrylic esters, methacrylic esters, and copolymers thereof, such as polybutyl acrylate or polyacrylic acid. 2-Ethyl to Kinru Lif? Vinyl ethylene copolymer (VAE)
, S)-polynorbornene-polyurethanes and silicone resin elastomers.

The polymeric material used to make the polymer layer - whether it is meltable or cross-linking, is a process, such as a chemical cross-linking agent.
Alternatively, it can be made non-fusible by radiation treatment such as high-energy electron beam irradiation, gamma ray irradiation, or ultraviolet irradiation.

The polymeric material used to make the polymeric layer may be partially transparent (at least to visible radiation) or completely opaque, or it may have an opacity anywhere between these extremes. If the opacity is improved by incorporating a small amount, say 5% by weight, of carbon black into the polymeric material, both the recovery and J-injury times of the textile will probably be reduced by the absorption of infrared radiation. The flame rate appears to decrease due to increased heating of the flame, so that the flame rate remains the same as in the case of fenestration.

As evaluated, the matrix material is selected taking into account various other desirable properties inherent in the polymeric material itself;
Antioxidant, UV stabilizer] 1. Anti-trunging (tra
It can be prepared with various adducts such as ccking agents and the like.

As mentioned above, the polymeric material of the composite structure softens to allow fiber recovery. This substance is preferably 2
0% secant modulus (at least I Q ”) VPa− and elongation at break (elon
ga[ion to break] at least 50%, preferably at least 100%, and both properties are measured at the recovery temperature of the fiber. In addition, the following inequality is satisfied at the recovery temperature of @lii woven fabric composite property or fiber.

In particular, it is smaller than 0.05.

where -X is the 20% secant modulus of the polymeric material (measured at a pulling rate of 300%/min) = Y is the recovery stress of the fiber (rec
R represents the average effective capacity fraction or related fraction of the heat recoverable fibers in the composite structure along a given direction based on the total capacity of the composite structure.

In another composite structure of the present invention, the mono-recovery knitted fabric provides the recoverable fibers in the recoverable composite structure, wherein the mono-recovery structure--the crosslinks imparting recovery properties thereto--are comprised of a polymeric material and The recoverable bridge can contain fibers.

Such resilient composite structures can be produced by applying a polymeric material to the fibers and then treating the polymeric material with the crosslinking process.

The fibers can be cross-linked to increase their strength after recovery, suitably with a recovery stress of at least 1 MPa/\ - preferably J5-5 MPa. The polymeric material is preferably treated with crosslinking to prevent it from running down or escaping during the heat recovery process, particularly from the flame implement. However, if the degree of cross-linking of the polymeric material is too high, it will reduce the recovery ratio of the composite. This can be problematic since different crosslinks in fiber and polymeric materials may need to be treated. This is because two-stage crosslinking requires separate treatments. This problem arises due to the different cross-linking responses (beam response in the case of radiation) and the processing history of the fibers and polymers, as well as the materials used for the fibers and polymer materials. This second effect involves a reduction in the fiber's beam response that occurs due to the orientation created by stretching the fiber to make it resilient.

Nevertheless - if the beam response of a recoverable fiber compared to the beam response of a polymeric material decreases before the recovery ratio of a composite structure decreases to a value of 70% of the recovery ratio of a non-release dimensioned composite feature. , the radial recovery stress of the fiber itself is at least l
If the beam response is such that it is possible to achieve M J' a - only one bridging process can be used to form a composite structure.

The relative beam response is determined by the prorad (p
rorads) and/or the presence of polymeric substances anLirads.

In a preferred embodiment of the invention, the textile is combined into a pliable, resilient composite structure comprising a resilient textile and an applied polymeric matrix material. In this embodiment - (a) the resilient knitted fabric is comprised of a cross-linked resilient polyolefin having a recovery stress of 15-5 MPa, and (1)) the matrix is the recovery ratio applied to the composite or the recovery applied to the free tail fabric. The crosslinking is treated so that the ratio is at least 65%, and the polymeric matrix material itself after radiation treatment - tensile rate 3
It has a hysteretic elongation of 400 to 700% measured at 0.00%/min.

In addition to providing a method of bridging, radiation treatment can impart other properties to a composite structure. Radiation treatment of the fibers, especially in the presence of oxygen, prior to application of the polymeric material causes changes in the surface properties of the fibers (such as oxidation), which improve the adhesion between the fibers and the polymeric material. . Also, the irradiation process after application of the polymeric material can aid in the bonding by forming bridges between the two components in the composite structure.

Alternatively, instead of relying on the conditions applied to the polymeric material, one can provide a certain number of ridge bonding between the fiber and the polymeric material.

The fiber preferably has a minimum recovery stress of 10 MPa at a temperature above the transition temperature of the fiber, more preferably 5 x 10-1 MI'a.
- usually at least 1 MPa - especially from 1,5 to 5 to LL'
Have a night of a. Theoretically, there is no upper limit to the recovery stress, but in practice the lowest value that can be achieved with polymeric fibers is 200.
MPa- more usually IQQMPa.

The heat recoverable fibers are preferably made from polymeric materials that impart good physical properties and qS to the fibers and good leap resistance. Olefin polymers such as polyethylene-ethylene copolymers, polyamides, polyesters, acrylic polymers and other polymers that can be crosslinked can be used. A particularly preferred polymeric material for use in fibers has a density of 0.94 to 0.97 grams/
cc-MW80×10~200×10, and 84n
It is based on polyethylene having a particle size of 5 x 10 to 30 x 103.

The recovery temperature of the fiber is preferably 60°C or higher,
Most preferably 80-250°C - for example 120-15
It is 0°C.

When the fibers are crosslinked by radiation, it is advantageous to incorporate a crosslinking step during the fiber manufacturing process. The fiber is extruded at a temperature below its melting point, preferably 800-20
The film is stretched to 0.00% and then cross-linked by radiation treatment.

Less preferred methods of manufacture include extruding the fibers, cross-linking them with radiation treatment, then heating the fibers preferably above their melting point, drawing the fibers, and cooling the drawn fibers. Approximately 5 to 35 megarads of high-density polyethylene fiber,
Preferably the radiation treatment is carried out at a radiation dose of about 5 to 25 megarads, especially about 7 to 18 megarads, especially about 10 to 18 megarads. Usually, the gel content in the cross-linked fibers is 20% or more, preferably 30% or more, and most preferably 40% or more. In practice, gel contents of 90% or more are not easily achieved.

In terms of heat recovery properties, the 11i fabric can be made from only heat recovery fibers as described above, or may contain other fibers in addition to the heat recovery fibers as described above. If the knitted fabric contains fibers other than heat-recoverable fibers, R in inequality (1) above relates only to the heat-recoverable fiber component. The knitted fabric can be knitted, woven, nonwoven, braided, etc.

In a preferred embodiment, the knitted fabric is a woven fabric. The fabric may include only heat recoverable fibers or may include heat recoverable fibers along with non-heat recoverable fibers or filaments. For example, a fabric can contain recoverable fibers in one direction and non-recoverable fibers in the other direction. This is to produce a heat recovery fabric that is recoverable in only one direction of the fabric. Non-recoverable fibers are - glass fibers,
Includes carbon paper af knee wire or other metal fibers - polyesters - aromatic polymers or imides and ceramics. A particularly preferred fabric is British Patent Application No. 8
No. 300219 and No. 8300222. Fabrics may be of any kind such as twill weave, broken weave, satin weave, satin weave, karami weave, plain weave, hompsunk, sack, cloak and various types of weave such as single or multi-layer weave, e.g. 2-3 layer weave. It can be woven with a combination of textile structures. As can be obtained by satin weaving, the recoverable fibers have many floats (for example 6 to 20
Fabrics containing the present invention are preferred as they appear to increase flame rate. In addition, the article may have multiple layers, for example, two or more knitted fabrics.
It can have three layers - separated by one or more layers of polymeric material.

If desired, the layer of polymeric material may be bonded to only one side of the heat-recoverable fabric, either by adhesive bonding, i.e., chemical or physical surface interaction, or by a mechanical interlocking process. Preferably, however, the heat-recoverable knitted fabric is encased in a polymeric material. That is, a polymer material surrounds the annular portion of the fiber surface area. Most preferably, the fabric is entirely surrounded by polymeric material, or in particular so that there is a limited thickness of polymeric material on each side of the fabric. In this case, the thickness of a single layer of polymer for the purposes of the invention is defined as the thickness of that portion of the layer present on the textile. In preferred articles according to the invention, the thickness of the polymeric material on the inside surface of the article on the side of the fabric opposite to the side receiving the flame is approximately 100% greater than the thickness of the polymeric material on the outside surface, on the opposite side of the fabric. The polymeric materials forming the top layer may be the same or different from each other, and a laminate of different polymer layers may be used on one or both sides of the fabric. The difference between two polymeric materials can be any one or more of the following: differences in thickness - differences in chemical type of polymer, and combinations of chemically identical types or processing methods. difference. There are two possibly contradictory schools of thought regarding the configuration of polymeric materials. The first is to set a single layer of polymer on the side facing the heating source in order to increase the flame rate of the #Jii1 fabric.The second is to set a matrix material that should not interfere with the inherent recovery of the knitted fabric. (for example, to make knitted fabrics impermeable).

The heat-facing layer is preferably bridging to prevent its escape or run-off, while bridging of the matrix generally inhibits recovery. In a preferred embodiment of the invention, varying degrees of cross-linking are provided between the flame exposed surface and the remaining surface of the polymeric material. This is achieved, for example, by forming a cross-linked thin layer on the outside, or by forming a cross-linked layer on one side of the fabric and an uncross-linked layer on the other side. Such an outer thin layer is an electronic screen (el
by using radiation with very low penetrating power, such as irradiation (electron curtain), or by cross-linking thin films on the surface of composite materials where the matrix is either uncross-linked or cross-linked to a lesser extent. This can be achieved by laminating the layers.

The different crosslinking processes in any of these embodiments can be accomplished by performing separate crosslinking steps for each layer to be crosslinked to a different degree. However, the single crosslinking is preferably achieved by a process, in particular a radiation treatment, which can be done if the beam responses of the different layers are (or are made to be) suitably different. For example, the majority of the matrix can be polypropylene (which is not crosslinked in this method) and only the surface layer (or only one side of the fabric) is polyethylene (which is crosslinked). Another method is to suitably load the various layers with prorads and/or ant 1 rads.A further feature is the use of meltable adhesives or sealants.
) (for example a real melt adhesive) or a mastic (such as a real melt adhesive) can be applied on the inner surface 11fj of the article to increase the thickness of the polymeric material on the inner surface of the article and/or to coat the inner surface. It has been found that applying a sealant or adhesive increases the flame rate of an article.

Examples of hot melt adhesives that can be used include monoethylene and vinyl acetate copolymer-based adhesives and polyamide-based adhesives. Such adhesives are well known and are disclosed, for example, in US Pat. No. 4,018,733 and US Pat. No. 4,181,775.

If desired, a heat cured vine adhesive can be used as the adhesive. An example of such an adhesive is disclosed in British Patent Publication No. 2104800.

Since the heat recovery properties of the articles of the invention are attributable to the recovery properties of the fabrics that make up the knitted fabric, the article as a whole does not need to be stretched during manufacture - the layers of such polymeric material are substantially The articles of the invention exhibit little or no tendency to spontaneously recover when heated. - It has the further significant advantage of being highly insensitive to the presence of small scratches on the surface, which may occur due to rough handling prior to combination setting. For comparison - e.g. It has been found that conventional heat shrink articles formed by crosslinking and then stretching - even with very small scratches on their surface, fail by tearing during heat recovery.

Heat recovery property η′, Iri! The fabric can be coated with a layer of polymeric material in a number of ways. For example, if the article is formed on each substrate piece, it may be preferable to apply the polymeric material to a knitted fabric by a press lamination process, or if the article is made from #JiN fabric of variable length. If possible, an extrusion laminate process is preferably used in which a hot polymeric material is pressed onto the fabric and immediately quenched to prevent recovery of the fabric - this operation is preferably carried out as a continuous process. In either case, sufficient heat and pressure must be applied to bond or interlock at least a major portion of the fabric - essentially all of it - with the polymeric material.

Other methods of coating KAM, 1rtlt objects with polymeric materials include saturated-solution coating-slurry coating-powder coating, reactive prepolymer (
For example, UV- or peroxide-activated acrylic prepolymers) can be used. In any bonding method employed, sufficient heating to cause significant recovery of the knitted fabric should be avoided unless the fabric is adequately inhibited from recovery.

Of the coating processes used, extrusion lamination appears to produce articles exhibiting particularly good flame rates and is preferred for that reason.

After coating the textile with the polymeric material - the polymeric material - preferably by high-energy electron beam irradiation or comma radiation, preferably from 0.5 to 15 megarads, especially 1
The crosslinking can be treated with a radiation dose of 10 to 10 megarads, especially 3 to 7 megarads, most preferably 1 to 5 megarads.

The article of the invention can be formed into many shapes depending on its intended use. Preferred applications include perimeter protection of cables and pipes or their joints or junctions.

Thus, the article of the invention may be tubular in shape or may have multiple positive sections, such as in the case of a cable break. If the article is designed to wrap around an elongated substrate with ends that cannot be easily reached - the article is manufactured as a so-called wraparound article in which the covering fabric has an open cross-section. I can do it. For example, it is substantially sheet-shaped and has two opposite end portions extending perpendicular to the recovery direction, the end portions being held together against the recovery forces of the tissue. What you can do is what you can do. The article can simply be wrapped around the substrate to be encapsulated, and the end portions are held together so as to wrap around the substrate in the shape of a cuff after the article has been heated. Wrapping articles made from knitted fabrics and suitable closure arrangements thereof are described in further detail in British Patent Application No. 83002.
It is disclosed in No. 23. In the case of an wrapper article in which the coated textile is in the form of a sheet, the article wraps around the substrate;
Is the opposite terminal part a bundle? , II7, the outer surface of the knitted fabric is limited to the outside. In general, the ability of a knitted fabric or a composite of knitted fabrics to be penetrated without tearing allows portions to be joined together (eg, to form a wrap) by mechanical bonding arrangements that extend through the single knitted fabric. Preferred arrangements are stitches or clasps.

Two types of articles of the invention are illustrated by way of example with reference to the accompanying drawings, in which: FIG.

FIG. 1 is a partially sectional perspective view of one type of article of the invention.

FIG. 2 is a partially sectional perspective view of a second type of article of the invention. FIG. 3 is a partial cross-sectional view of a third type of article of the invention.

FIG. 4 is a graphical representation of recovery power versus time for a knitted fabric of the present invention and a conventional heat recovery article.

With reference to the accompanying figures 1-3, figure 1 shows heat recoverable warp fibers 1
A type of knitted article is shown in which a fabric 1 consisting of and heat-stable weft fibers 2 is coated on its outer surface with a layer 3 of heat-softening polymer. FIG. 2 shows a fabric similar to that of FIG. 1 but additionally having an adhesive underlayer 4. FIG. FIG. 3 shows an article of the same type described above, but with a layer 3 of heat-softening polymer extending beneath the fabric so as to completely encapsulate the fabric. In articles of this type, the corresponding thickness of the polymer layer is the thickness of that portion of the layer overlying the fabric.

The flame rate in the examples below is determined by the following procedure: Instron (trade name) Tensile Test or Mounting A square coated fabric sample of dimensions 100 m+, q x 100 mm is placed between the fixtures, and its resilient fibers are subjected to a tensile test. , trial court 1
4j: and so that the outer surface of the fabric was positioned approximately 128 mm'141L from the propane gas flame. Protect the seams on the vertically stretched side of the fabric sample from flames with a metal plate! Then, expose only the middle part of the IS with a width of 96 mm to the flame. Before lighting the flame tool, place a temporary metal plate to completely darken the sample from the flame. Light the flame tool and travel length approximately 260
nnn - the speed at which the flame passes along the sample approximately 1 time/1
Move the flame continuously across the sample from one side to the other in seconds. Except for the temporary metal plate, the resilient fabric is mounted at regular intervals in a tensile testing machine to apparently project the applied force as a time scale.

A typical graph of resilience versus time is shown in the accompanying drawings.
A heat-recoverable fabric (Pron II) and a conventional heat-shrinkable sheet (Pron), designated as I[). This graph effectively represents the forces exerted by the heat-shrinkable seam portion in the center of the seam, where the seam is unable to recover to any significant extent due to the relatively large diameter of its center.

As the article is heated by the flame, the resiliency of the article increases until it reaches the maximum value (point A, 8'), and then the resiliency decreases, and the degree of decrease in the resiliency is the same as before the sample is damaged. The minimum value (points 13, 13') is reached in a short time. Damage to a normal sheet-type article is that when the article is torn, the recovery power is 0 (point C
damage of the articles of the present invention is observed as a substantially linear decrease in recovery force (region C) as the fibers become progressively damaged.

The curve at the maximum recovery force and the maximum slope of the curve (point T), I
)') The time corresponding to the horizontal tangent section where the extrapolated straight line touches '1ill! , 1 point is recorded as one recovery time. In the case of a normal article, the second point on the time axis corresponds to a sudden decrease in recovery power (point E), or in the case of the article of the present invention, the tangent at the minimum recovery reduction rate and the fiber loss 1α (point E). The intersection between the tangents of the recovery decrease after starting is considered the damage time.

Unknown IB Store (The flammability rate of this article is the ratio of the damage time to the recovery time for that article (or as shown in a graph)'/
X value).

Next, preferred embodiments of the present invention will be specifically described with reference to Examples.

Examples 1 to 6 High-density polyethylene monofilament with a diameter of 0.29 mm was used as the warp yarn and 75Eω crow yarn was used as the weft yarn. l Make a diagonal fabric. This fabric is densely rutted.
180/12 (80 warp fibers per inch / 12 weft fibers per inch or 3 J, 5/4
．． 7 (per cm). Irradiation speed of the fabric) H~
The polyethylene fibers were irradiated with a dose of 1.5 MeV 'electron beam 15 Megarads' at 100 Megarads/min. As a result, the polyethylene fibers had a gel content of 37.3%, measured after refluxing in Kinshin.
- and 100% secant modulus at 150°C, Q, 5 Q
It was MPa. The thickness of the fabric was 0.6 mm.

This fabric was flame treated as described above and its flame rate was measured, and the results are shown in Table 1.

On each side of the fabric - equal thickness of pure low-density polyethylene (M, F, I, = 3.0) + number average molecular weight Mn - 14,800 - weight average molecular weight MW = 11
4.800) to form a laminate and then irradiated with high energy electrons to a further dose of 3 rad to give the products of Examples 2-6. The flame rate value is shown on the front surface. It can be seen from Table 1 that the coated fabric is substantially more flameable than the uncoated fabric and the flame rate increases with the thickness of the polyethylene coating.

Table 1: The uncoated fabric (Example 1) showed a low flame rate, and the fabric recovered and was damaged for several seconds by the solder, making it unacceptable for the test. Become.

Examples 6 to 9 Prior to the press lamination process in Examples 2 to 6, each side of the fabric was similarly extrusion laminated with pure low density polyethylene (melting point 260'C) and immediately quenched. The process for preventing recovery of the fabric is then carried out, and the operations in Examples 2 to 6 are repeated. The thickness of the extrusion laminated fabric is 0.75++++++. The results are shown in Table ■.

From this it can be seen that extrusion laminated samples generally exhibit significantly higher flame rate values than purely press laminated samples.

Table ■ Examples 10 to 14 Press-laminate low-density polyethylene on a fabric A layer of polymer containing 2% by weight of carbon black (so that it becomes black and completely opaque) is formed on the fabric. Otherwise, the operations in Examples 6 to 9 are repeated. The results are shown in Table ■.

Table ■ Examples 15 to 16 Using fabrics with different 24 (hand-woven and satin) weave designs, the procedure of Example 10 was repeated. The results are shown in Table ■. It can be understood from this that articles made of ten woven cloth exhibit the highest flame rates. Table IV Example 17 Press laminate forming layer of low density polyethylene is replaced by that of medium density polyethylene - otherwise Example 1
Repeat step 5. The flame rate was 3.2.

Examples 18-20 The operation of Example 10 plus +0.13 before flame treatment
The fabric was made by pulling the fabric across the fabric in a direction perpendicular to its direction of recovery using a 405 g load with a surface with a sharp knife edge that protruded by ~0.14 mm. A single bow wound 5 to 6 cm long is formed on the outer surface, and the same operations as in Example 10 are repeated except for the following.

For comparison, a common heat-shrinkable sheet used as a seam for telecommunication cables was flame treated under similar conditions.

This heat-shrinkable sheet (with a single force) will not be easily removed (
Example 19) or C pulling force) scratching (Example 20). The results are shown in Table V (Table V). Having a higher flame rate than sheets (g), this textile article is also quite insensitive to the presence of scratches, whereas regular sheets cannot recover from scratches (g). .

Table V Note) ・Re is the same as in Example 10.

[Brief explanation of the drawing]

1 to 3 are drawings showing articles of the present invention, in which FIG. 1 is a partial cross-sectional perspective view of a first type article, FIG. 2 is a partial cross-sectional perspective view of a second type article, and FIG. 3 is a third type article. FIG. 3 is a partial cross-sectional view of the article. FIG. 4 is a graph showing the resilience of the article over time. ]... Warp yarn 21su III, 2... Weft yarn thread -1
3. Polymer 1st. [3,i ;'l・'Iv''1j'Zan (no change to Shiroishi) Figure 3゜Continued from page 1Priority claim @July 22, 1983 ■United Kingdom (GB
) [Yes] 8319855 @ August 16, 1983 ■ United Kingdom (GB) ■ 8322004 0 Inventor James L--Mass Triplett 2801 Superior Drive, Livermore, California 94550 United States of America 1976; March 1'' 711 Patent Office Officer 1 Display of Case 1939 Patent Application No. C1i 23 S 2 Name of Invention Heat Recoverable Article 3 Relationship with the Amendment Case Patent Applicant 11 (Ikirisu, England, London E.C. 1.1 N.L., Fenotar Lane, Rolls.
Bildinges No. 7, Roll 7, Heins Name 1 Shi/1 Kem Rimiteno F 4 Agent 5 Date of Sleeve Correction Order 2 Voluntary

Claims (1)

Claims: 1. A textile fabric comprising fibers which recover in size after heating and have a tensile strength at the recovery temperature of at least Q, l MPa, the fabric having a j of at least 0.03 mm.
at least one of the substrates, characterized in that it has an outer shell stone coated with a layer of a polymeric material of 1000 mL, the polymeric material being softened without flowing when heated to enable recovery of the article; A dimensionally heat recoverable article for wrapping a part. 2. The layer of polymeric material is at least 0.07 wrr=
The article according to claim 1, having a thickness of . 3. The article of claim 2, wherein the single polymer layer has a thickness of at least 0.1 mm. 4. The article of claim 3, wherein each polymer layer has a thickness of at least 0.2 TTun. 5. An article according to any one of claims 1 to 4, wherein each polymer layer has a thickness not exceeding 2 mm. 6. The article according to any one of claims 1 to 5, wherein the single polymer layer has a softening point below the recovery temperature of the fiber. 7. An article according to any one of claims 1 to 6, wherein the knitted fabric has a layer of polymeric material on each side thereof. 8. An article according to claim 7, wherein the tissue has a layer of polymeric material on its inner surface that is about as thick as the layer of polymeric material on its outer surface. 9. A layer of polymeric material on the outer surface of the knitted fabric or 10.
9. An article according to any of claims 1 to 8, comprising an ethylene homopolymer or copolymer having a density not exceeding 94 PCC. 10. Extrusion coating method of applying a single layer of polymer to knitted fabric.
10. An article according to any one of claims 1 to 9 applied by spray coating, dip coating or sheet lamination. 11. The article according to any one of claims 1 to 10, wherein the heat-recoverable fibers are made from stomach-density polyethylene. 12. 12. An article according to any of claims 1 to 11, wherein the il'J6f fabric includes dimensionally thermostable fibers. 13. The article of claim 12, wherein the thermally stable fibers are dimensionally oriented substantially perpendicular to the thermally recoverable fibers. 14. The article according to any one of claims 1 to 13, wherein the knitted fabric is woven into a plain weave, twill weave, broken pattern weave, or satin weave. 15. The article according to claim 14, wherein the knitted fabric has a satin Ni weave. 16. An article according to any of claims 1 to 15, wherein the material of the single layer of 16 bolymer is substantially stress-free. 17. The article according to any one of claims 1 to 16, which has a tubular outer shape. 18. Any of claims 1 to 16 in the form of an enclosure extending substantially perpendicular to the direction of recovery of the article and having opposite ends that can be left together during use. Articles described in Crab. 19. The composite structure is comprised of a polymeric matrix material and heat recoverable fibers having the advantage of making the composite structure heat recoverable;
A dimensionally heat recoverable article comprising a composite structure, characterized in that the crosslinking has been treated to such an extent that the outwardly facing surface layer of the polymeric matrix material is more distinct from the remainder of the polymeric matrix material. . 20. The article of claim 19, wherein the polymeric matrix material is cross-linked by radiation treatment. 21. The article of claim 20, wherein different degrees of crosslinking result from different beam responses of different regions in the polymeric matrix. (t )) A method of surrounding at least a portion of a substrate, the method comprising heating the composite structure with an open fire or hot air gun to restore the structure to engagement with the substrate. 23. The method of claim 22, wherein the composite structure comprises the article of any of claims 1-21. 24. The method according to claim 22 or 23, wherein the base material includes a pipe or a cable, or a joint or seam thereof.