JP2856641B2 - Two-component adhesive for synthetic resin lining and method for producing synthetic resin lining tube - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-part adhesive composition suitable for manufacturing a synthetic resin lining tube obtained by bonding a synthetic resin tube to the inner surface of a metal tube with an adhesive, and such a synthetic resin lining. The present invention relates to a method for manufacturing a pipe, and more particularly to a method for manufacturing a two-part adhesive composition for a synthetic resin lining and a synthetic resin lining pipe capable of improving heat resistance and durability between a synthetic resin pipe and a metal pipe.

[0002]

2. Description of the Related Art Conventionally, a synthetic resin lining tube has been manufactured by a method called an expansion method or a diameter reduction method.

In the swelling method, an adhesive is interposed between the outer peripheral surface of the synthetic resin tube and the inner peripheral surface of the metal tube, and the inside of the synthetic resin tube is expanded by heating and pressurizing to bond the two. (For example, JP-A-56-55227, JP-A-58-12720). On the other hand, in the diameter reduction method, the metal pipe is reduced in diameter with a roll or the like in a state where an adhesive is interposed between the outer peripheral surface of the synthetic resin pipe and the inner peripheral surface of the metal pipe. The surface and the inner peripheral surface of the metal tube are pressed and bonded.

In order to improve the corrosion resistance of the above-mentioned synthetic resin-lined pipe, a styrene-butadiene-styrene triblock copolymer (SB) is used as the adhesive.
A rubber-based hot-melt adhesive obtained by adding a tackifier resin or the like to a synthetic rubber such as S) is known (Japanese Patent Publication No. Hei 2-
37378, etc.).

[0005] As a method for obtaining a synthetic resin-lined tube using the rubber-based hot melt adhesive as described above, there are the following methods.
Guide the synthetic resin tube to a crosshead die having an annular discharge port, and extrude the adhesive into a cylindrical shape from the crosshead die,
A method of coating the entire outer peripheral surface of a synthetic resin tube is known (JP-A-56-1515285).

On the other hand, as a hot-melt adhesive capable of improving heat resistance, a reaction-curable polyester-based hot-melt adhesive obtained by mixing a carboxylic acid-containing polyester resin with an epoxy resin and a curing agent, and heating and crosslinking and curing the mixture. Are known. In this case, as the curing agent, dicyandiamide, 3- (3,4-dichlorophenyl) -1,1
-Nitrogen-containing compounds such as urea-based curing accelerators such as dimethylurea and imidazole-based curing accelerators are used.

As a reaction accelerator for accelerating the reaction between the carboxylic acid and the epoxy group, chromium (II)
I) Tricarboxylate is known to be preferable (Japanese Patent Application Laid-Open No. 50-53291).

[0008]

However, when the above rubber-based hot melt type adhesive is used, if a vinyl chloride-based synthetic resin tube is used as the synthetic resin tube, the adhesiveness to the metal tube is not sufficient. That is, upon cooling after heating and bonding the vinyl chloride-based synthetic resin tube to the steel tube, the steel tube and the vinyl chloride-based synthetic resin are easily separated from each other and have insufficient heat resistance, so that they are easily separated by a high-temperature impact or the like. was there.

In the above reaction-curable polyester hot-melt adhesive, when the synthetic resin tube to be adhered is made of a chlorine-containing resin such as a vinyl chloride resin, the chlorine-containing resin is removed by heating. Since the chlorine reaction and the dehydrochlorination reaction are promoted, there is a serious problem that the chlorine-containing resin is deteriorated.

[0010] Further, in the above-mentioned reaction-curable polyester hot-melt adhesive, a considerable time and a considerable temperature are required for curing unless a nitrogen-containing curing accelerator is present. There was a problem that productivity was low. In addition, since it is necessary to cure under the above-mentioned high temperature conditions, there is a possibility that the synthetic resin to be lined may be thermally degraded. As a catalyst for solving such a problem, that is, a curing accelerator, the above-mentioned chromium (II)
I) It has been proposed to use tricarboxylate. However, when chromium (III) tricarboxylate is used, the curing reaction takes place near room temperature, so that the curing proceeds considerably at the time of compounding and applying the adhesive. Therefore, it has been difficult to actually use the synthetic resin-lined pipe in the production thereof.

Further, since it is difficult to form the above-mentioned reaction-curable polyester-based hot-melt adhesive into a film, the adhesive cannot be extruded into a cylindrical shape from the above-described crosshead die having an annular discharge port. . That is, the outer peripheral surface of the synthetic resin pipe could not be efficiently covered using the crosshead die having the annular discharge port.

[0012] An object of the present invention is to provide a lining of a vinyl chloride resin on the inner surface or outer surface of a metal tube.
Use of an adhesive composition for a synthetic resin lining, and an adhesive composition for such a synthetic resin lining, which enable efficient and inexpensive production of a synthetic resin lining tube having excellent durability, especially thermal shock resistance and water resistance. To provide a method for manufacturing a synthetic resin lining tube.

[0013]

Means for Solving the Problems The inventors of the present application have made intensive studies to achieve the above object, and as a result, a specific composition A containing a crystalline saturated polyester resin reacted with an epoxy group-containing compound has been identified. It has been found that it is possible to obtain a synthetic resin-lined tube having excellent thermal shock resistance and water-resistant adhesiveness by blending the epoxy group-containing compound B of the present invention, and the present invention has been accomplished.

That is, the two-part adhesive composition for lining a synthetic resin according to the first aspect has a carboxyl group equivalent of 300 to 4000 and a weight average molecular weight of 1,000 to 1,000.
6000, a crystalline saturated polyester resin having a melting point of 30 to 90 ° C., and having two epoxy groups in the molecule, wherein the number of epoxy groups is 0.2 to 0.9 times the number of carboxyl groups in the polyester resin. A composition A obtained by reacting a certain amount of an epoxy group-containing compound in the presence of a curing accelerator, and an epoxy group-containing compound B having three or four epoxy groups. Compound B
Is 5 to 100 parts by weight of the saturated polyester resin
A two-pack type adhesive composition for a synthetic resin lining in which the content is in the range of 50 parts by weight and the epoxy group-containing compound B accounts for 10 mol% or more of the total of the saturated polyester resin and the epoxy group-containing compound B. It is.

In a second aspect of the present invention, there is provided a method of manufacturing a synthetic resin-lined pipe, wherein the adhesive composition according to the first aspect of the present invention is used. The adhesive composition is extruded into a cylindrical shape from a crosshead die having an annular discharge port to obtain a synthetic resin tube coated with an adhesive by coating the outer peripheral surface of the synthetic resin tube led to the crosshead die. After inserting the synthetic resin tube coated with the adhesive into the metal tube, the metal tube is reduced in diameter, and the synthetic resin tube is heated and bonded to the inner surface of the metal tube. It is.

The details of the first and second aspects of the present invention will be described below. The two-component adhesive composition for a synthetic resin lining The saturated polyester resin used in the invention of claim 1 has a main chain of essentially-(R-CO
O)-is a crystalline saturated polyester resin comprising an ester bond (wherein R represents a divalent hydrocarbon group), and has a carboxyl equivalent of 300 to 400 as described above.
0 and a weight average molecular weight in the range of 1,000 to 6,000 is used.

The carboxyl equivalent is less than 300,
If the weight average molecular weight is less than 1,000, the crosslink density of the final cured product becomes high, and the elastic modulus of the cured product becomes too high, so that adhesive peeling is likely to occur due to thermal stress applied to the lining tube.

On the other hand, when the carboxyl group equivalent is larger than 4000 and the weight average molecular weight is larger than 6000, the crosslink density becomes too low, the heat resistance of the cured product is reduced, and the adhesive peeling is also caused by the heat applied to the lining tube. Occurs.

When the melting point is lower than 30 ° C., the curing of the adhesive composition gradually proceeds at room temperature due to the action of a curing accelerator. A negative effect on tube performance.

On the other hand, if the melting point is higher than 90 ° C., the temperature required for curing becomes high, so that the lining resin suffers from thermal deterioration,
Increasing the modulus of elasticity of the final cured product by the crystal has an adverse effect such as a decrease in the tube performance of the synthetic resin lining tube.

The epoxy group-containing compound used in the composition A and the epoxy group-containing compound B of the adhesive composition of the present invention includes bisphenol type epoxy resin,
Novolak type epoxy resins, aliphatic epoxy resins, alicyclic epoxy resins and the like can be mentioned, and one or more of them can be used.

The reason why the specific epoxy group-containing compound is added to the composition A is to extend the main chain of the polyester resin and increase the elongation at break of the cured product. Also, the reason that the epoxy group-containing compound is added so that the number of epoxy groups is 0.2 to 0.9 times the number of carboxyl groups in the polyester resin is less than 0.2 times, the effect is not sufficiently exhibited. Conversely, if it exceeds 0.9 times, the number of epoxy groups involved in the curing reaction decreases, the degree of crosslinking becomes too small, and the heat resistance becomes insufficient.

The reason that the epoxy group-containing compound B is blended in the range of 5 to 50 parts by weight based on 100 parts by weight of the saturated polyester resin is that if less than 5 parts by weight, the saturated polyester resin which does not participate in the reaction remains in the system. On the contrary, if it exceeds 50 parts by weight, the epoxy group-containing compound which does not participate in the reaction remains, and in any case, heat resistance and water resistance decrease.

The reason why the content of the epoxy group-containing compound having 3 or 4 epoxy groups in the molecule is 10 mol% or more of the whole resin is that if the amount is less than 10 mol% of the total amount, Is too small, and the heat resistance is not sufficient. The number of moles in this case is calculated based on the weight average molecular weight.

When an epoxy group-containing compound having 5 or more epoxy groups in the molecule is used, the crosslink density becomes too high, the elasticity of the cured product becomes high, and the thermal shock resistance of the adhesive becomes low. descend. Therefore, it is preferable not to contain an epoxy group-containing compound having 5 or more epoxy groups in the molecule. Even if a compound containing five or more epoxy groups is contained in the molecule, it is preferable to keep the content to 1 mol% or less of the whole resin.

Examples of the epoxy group-containing compound having three or four epoxy groups in a molecule include trimethylolpropane triglycidyl ether, tetrakis (glycidyloxyphenyl) ethane, triglycidyl (trishydroxyethyl) isocyanate, and the like. Glycerol triglycidyl ether, sorbitol triglycidyl ether, sorbitol tetraglycidyl ether, pentaerythritol triglycidyl ether, pentaerythritol tetraglycidyl ether, diglycerol triglycidyl ether, tris (glycidyloxyphenyl) methane, phenol novolak type having a polymerization degree of 3 and 4 Epoxy resins, cresol novolak type epoxy resins having a degree of polymerization of 3 and 4, and the like can be mentioned. These epoxy group-containing compounds can be used alone or as a mixture of two or more.

The curing accelerators include chromium (III) hexanoate, chromium (III) pentanoate, chromium (III) butyrate, and chromium 2-ethylhexanoate (I
II), chromium (III) decanoate, chromium (III) oleate, chromium (III) stearate, chromium (III) toluate, chromium (III) cresylate,
Chromium (III) tricarboxylate compounds such as chromium (III) benzoate, chromium (III) alkyl benzoate, chromium (III) alkoxy benzoate, chromium (III) naphthenate, chromium (III) alkoxide, di-isopropoxy Bis (acetylacetonate)
Titanium, isopropoxy (2-ethylhexanediolate) titanium, di-n-butoxy-bis (triethanolaminate) titanium, hydroxybis (lactate) titanium, titanium chelate compound, triphenylphosphine, aluminum (III) acetyl Examples include, but are not limited to, acetonates.

In use, the composition A and the epoxy group-containing compound B may be mixed at the above-described predetermined ratio and applied to the outer surface or the inner surface of a synthetic resin tube as an adherend. Does not matter. Further, the composition A and the epoxy group-containing compound B can be blended at a temperature higher than any melting point of the composition A and the epoxy group-containing compound B, and at a temperature of 100 ° C. or less,
The stability after mixing the two components is also sufficiently maintained. further,
After the composition A and the epoxy group-containing compound B are mixed and applied, curing is performed using the composition A and the epoxy group-containing compound B.
And proceeds at a temperature of 200 ° C. or lower. Therefore, it is possible to maintain a good balance between the composition A and the mixing, coating, and curing (productivity) of the epoxy group-containing compound B.

[0029] In the invention according to the manufacturing method according to claim 2 of synthetic resin lining pipe, first, providing a 2-part adhesive composition according to the invention described in claim 1. That is,
The composition A and the epoxy group-containing compound B are mixed at a ratio of 5 to 50 parts by weight of the epoxy group-containing compound with respect to 100 parts by weight of the saturated polyester resin to obtain an adhesive. This mixing is performed at a temperature higher than the melting point of each of the composition A and the epoxy group-containing compound B and in the range of 100 ° C. or less.

Next, a step of applying the obtained adhesive to the outer peripheral surface of the synthetic resin tube is performed. This step is performed by extruding the adhesive into a cylindrical shape from a crosshead die having an annular discharge port and covering the entire outer peripheral surface of the synthetic resin pipe led to the crosshead die. The process itself using a crosshead die is conventionally known as disclosed in JP-A-56-151528. Therefore, the adhesive can be applied to the outer peripheral surface of the synthetic resin tube according to the above-mentioned conventionally known method.

Then, after inserting the synthetic resin tube whose outer peripheral surface is covered with the adhesive into the metal tube, the inner peripheral surface of the metal tube and the synthetic resin tube are reduced by, for example, reducing the diameter of the metal tube using a roll. Is pressed against the outer peripheral surface. Then, after diameter reduction, the adhesive is heated and cross-linked and cured at a temperature higher than any melting point of the composition A and the epoxy group-containing compound B and at a temperature of 200 ° C. or less, and the synthetic resin tube is attached to the inner peripheral surface of the metal tube. Adhere firmly. In this manner, a synthetic resin-lined pipe can be obtained according to the second aspect of the present invention. The individual processing operations in each of the above-described steps can be performed according to a conventionally known method for manufacturing a synthetic resin-lined pipe.

[0032]

The two-component adhesive composition for lining a synthetic resin according to the first aspect of the present invention is an epoxy resin having three or four epoxy groups per 100 parts by weight of the specific crystalline saturated polyester resin. The group-containing compound is 10 to the total of the saturated polyester resin and the epoxy group-containing compound B.
Since it is blended so as to account for at least mol%, crosslinking proceeds sufficiently, and the heat resistance of the cured product is enhanced.

In the first aspect of the present invention, since a crosslinking agent such as the above-mentioned nitrogen-containing compound is not required as a curing accelerator, for example, a chlorine-containing resin such as a vinyl chloride resin is used as an adherend. Does not promote the dechlorination reaction or dehydrochlorination reaction. Therefore, the chlorine-containing resin does not deteriorate during heat bonding.

Further, since the melting point of the crystalline polyester resin used in the composition A is in the range of 30 to 90 ° C., the stability after mixing the two components is secured, and the curing temperature is relatively low. Temperature. Therefore, it is possible to provide an adhesive in which the mixing, application, stability and curing time are well balanced.

Further, in the above-mentioned adhesive composition, since the cured product forms a layer having high flexibility, which is mainly composed of polyester, the stress generated by the difference in linear expansion coefficient between the metal tube and the synthetic resin is reduced. be able to.

According to the second aspect of the present invention, since the synthetic resin pipe is heated and adhered to the inner peripheral surface of the metal pipe using the two-component adhesive composition for synthetic resin lining as described above, the synthetic resin lining is used. The thermal shock resistance and water resistance of the tube are enhanced. According to the second aspect of the present invention, the two-part adhesive composition is extruded from a crosshead die and coated on the outer peripheral surface of the synthetic resin pipe, and then the synthetic resin pipe and the metal pipe are bonded. Therefore, since the adhesive composition cures at a relatively low temperature, the productivity of the synthetic resin-lined pipe can be increased.

[0037]

The present invention will be clarified below by describing non-limiting examples of the present invention. In the following description, “parts” means “parts by weight” unless otherwise specified.

The formulation No. shown in Table 1 below 1 to 7 two-pack adhesive compositions were prepared.

[0039]

[Table 1]

The details of each component of the composition A and the epoxy group-containing compound B in Table 1 are as follows. Saturated polyester resin: Huels product name: Dyn
acoll 8330, average molecular weight 4000, acid value about 2
8, melting point 40 ° C.) Tactics 742: a semi-solid trifunctional epoxy resin compound manufactured by Dow Chemical Japan, epoxy equivalent = 160.

Epicoat 1001: Bisphenol A type solid epoxy resin manufactured by Yuka Shell Epoxy Co., epoxy equivalent = 450. Accelerator AMC-2: Chromium (III) tricarboxylate, manufactured by Aerojet General Corporation.

In the above Formulation Examples 1 to 6, the above-mentioned saturated polyester resin, accelerator AMC-2 and Epicoat 1001 were blended at the above-mentioned predetermined ratio,
After kneading at a temperature of 10 minutes to prepare composition A, the mixture was mixed with tactics 742 at the above-mentioned predetermined ratio at a temperature of 80 ° C. for 3 minutes.

In addition, Formulation Example 7 was prepared by kneading a saturated polyester resin and dicyandiamide, then compounding Epicoat 1001 at the ratio shown in Table 1, and mixing by heating at a temperature of 150 ° C. for 5 hours.

The number of epoxy groups / the number of COOH in composition A in Formulation Examples 1 to 7 and 3 to 4 in Formulation Examples 1 to 7
The mole% of each epoxy group-containing compound is shown in Table 1. The following Experimental Examples 1 to 3 were performed using the adhesive compositions of the above Formulation Examples 1 to 7, and each adhesive composition was evaluated.

EXPERIMENTAL EXAMPLE 1 5 g of each of the adhesives of Formulation Examples 1 to 7 were sandwiched between polyethylene terephthalate films whose surfaces had been subjected to release treatment.
At a temperature of 3 kg / cm ^{2 and} hot-pressed for 1 minute to form an adhesive film having a thickness of 50 μm. The obtained adhesive film was placed on a chlorinated vinyl chloride resin plate having a glass transition point of 120 ° C. and a vinyl chloride resin plate having a glass transition point of 80 ° C., and placed in an oven at 150 ° C.
After standing for a minute, it was taken out of the oven, and the appearance of the chlorinated vinyl chloride resin plate and the vinyl chloride resin plate were visually observed.

The results are shown in Table 2 below.

[0047]

[Table 2]

As is clear from Table 2, in Formulation Example 7,
Black discoloration occurred on the chlorinated vinyl chloride resin plate and black discoloration and foaming occurred on the vinyl chloride resin plate, whereas in Formulation Examples 1 to 6, no change was observed on the chlorinated vinyl chloride resin plate, and In the vinyl chloride resin plate, the color only changed to pale yellow.

Experimental Example 2 Each of the adhesives of Formulation Examples 1 to 6 was applied on a Teflon sheet and cured at a temperature of 80 ° C. for 60 minutes to obtain a 1 mm thick flat cured product. The obtained plate-shaped cured product is 5 mm wide ×
A test piece was cut out to a length of 60 mm. About the obtained test piece, at the temperature of 23 degreeC and 85 degreeC,
The maximum elongation and the stress at 50% elongation were measured at a tensile speed of 50 mm / min. The results are shown in Table 3 below.

[0050]

[Table 3]

As is clear from Table 3, in Formulation Example 6,
It can be seen that the maximum elongation is as small as 19% even at 23 ° C., and hardly elongates at 85 ° C. as 0%. Therefore, it is difficult to have flexibility and the flexibility at high temperature is extremely low. In addition, in Formulation Example 5, the maximum elongation at 23 ° C. is 102
Although relatively large at 3%, at 85 ° C., 102%
%, Which indicates that the thermal shock resistance is not sufficient. On the other hand, it can be seen that, in Formulation Examples 1 to 4, the decrease in the maximum elongation at 85 ° C. is small, and the stress at 50% elongation is sufficiently small at 85 ° C. and has sufficient flexibility.

Experimental Example 3 Each of the adhesive compositions of Formulation Examples 1 to 6 was prepared using an outer diameter of 54.5 mm ×
The outer peripheral surface of a chlorinated vinyl chloride resin tube having a thickness of 3 mm and a length of 300 mm was coated to a thickness of 100 µm. Next, the chlorinated vinyl chloride resin tube coated with the adhesive was passed through an outer diameter of 63.5.
mm, a thickness of 3.5 mm and an inner diameter of 56.5 mm were inserted into a steel pipe, and the outer diameter of the steel pipe was reduced to 60.5 mm by a diameter reducing roll. Thereafter, the reduced-diameter synthetic resin-lined steel pipe was put into an oven at 80 ° C., taken out one hour later, and allowed to cool at room temperature to obtain a synthetic resin-lined steel pipe.

The obtained synthetic resin-lined steel pipe was subjected to 25
5 minutes in hot water at 85 ° C
The step of dipping for 1 minute was defined as one cycle, and after 300 and 1000 cycles, a cylindrical portion having a length of 2 cm was cut from the end of the synthetic resin-lined steel pipe. After a while
After the cylindrical portion was dried, it was divided into 12 equal parts in the circumferential direction to obtain divided pieces (divided pieces Nos. 1 to 12 in Table 4 described later), and the shear strength of the adhesive portion in each divided piece was measured at 25 ° C and the loading rate. It was measured at 20 kg / sec. The results are shown in Table 4 below.

[0054]

[Table 4]

As is clear from Table 4, the chlorinated vinyl chloride resin pipe and the steel pipe were firmly adhered to each other even when the number of cooling and heating cycles was 300 or 1000, when the blending examples 1 to 4 were used. However, in Formulation Example 6, the chlorinated vinyl chloride resin pipe was not substantially adhered to the inner surface of the steel pipe, and in Formulation Example 5, variation in the adhesive strength in the circumferential direction was observed after 300 cycles of cooling and heating. Further, it can be seen that the adhesion strength in the circumferential direction became remarkable after 1000 cycles, and that some parts were not bonded.

[0056]

According to the first aspect of the present invention, there is provided a composition comprising the above specific crystalline saturated polyester resin as a main component and an epoxy group-containing compound having two epoxy groups in the above specific ratio. Since the epoxy group-containing compound having three or four epoxy groups is mixed with the product A at the above-described specific ratio, the heat resistance of the cured product is effectively increased by heat crosslinking and curing. In addition, since the heat-crosslinking curing does not accelerate the dechlorination reaction and dehydrochlorination reaction of the chlorine-containing resin and has an appropriate pot life and curing time, it is particularly preferable to use chlorine such as vinyl chloride resin. It can be suitably used as a heat-resistant adhesive composition for applying a resin lining to a metal tube using the contained resin.

According to a second aspect of the present invention, since the synthetic resin lining pipe is manufactured using the adhesive composition according to the first aspect of the present invention, the synthetic resin pipe is made of a chlorine-containing resin. Even when the pipe is used, a synthetic resin lining pipe having sufficient thermal shock resistance can be obtained. In addition, since the adhesive composition has a long pot life and the curing proceeds at a relatively low temperature, the adhesive composition is extruded into a cylindrical shape from a crosshead die, and the outer peripheral surface of the synthetic resin tube is formed. , And the adhesive can be applied, so that the production efficiency of the synthetic resin lining tube can be increased.

Continuation of front page (56) References JP-A-5-43859 (JP, A) JP-A-5-112765 (JP, A) JP-A-5-156229 (JP, A) JP-A-5-247428 (JP) JP-A-6-733360 (JP, A) JP-A-6-313160 (JP, A) JP-A-7-26239 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB Name) C09J 163/00-163/10 B21D 51/18

Claims (2)

(57) [Claims] 1. A carboxyl equivalent of 300 to 4000.
Having a weight average molecular weight of 1,000 to 6,000,
It has a crystalline saturated polyester resin having a melting point of 30 to 90 ° C. and two epoxy groups in the molecule, and the number of epoxy groups is 0.2 to 0.1% of the number of carboxyl groups in the polyester resin.
A composition A obtained by reacting a 9-fold amount of an epoxy group-containing compound in the presence of a curing accelerator, and an epoxy group-containing compound B having 3 or 4 epoxy groups, The content of the epoxy group-containing compound B is in the range of 5 to 50 parts by weight based on 100 parts by weight of the saturated polyester resin, and the amount of the epoxy group-containing compound B is 10 to the total of the saturated polyester resin and the epoxy group-containing compound B. A two-component adhesive composition for a synthetic resin lining, which accounts for at least mol%. 2. The synthetic resin lining two-component adhesive composition according to claim 1 is extruded into a cylindrical shape from a crosshead die having an annular discharge port, and the synthetic resin tube is guided to the crosshead die. A synthetic resin tube coated on the outer peripheral surface and coated with an adhesive is obtained. After inserting the synthetic resin tube coated with the adhesive into the metal tube, the diameter of the metal tube is reduced. A method for producing a synthetic resin-lined pipe, characterized by heating and bonding.