JP2004189939A - Weld covering material, joint structure, welding method, welded article and composite article - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a weld covering material which allows little permeation of chemical solution at a sheet-joining part, is excellent in welding reliability and generates no leaking part and a welding method in which the weld covering material covers a matrix. <P>SOLUTION: The weld covering material is composed of a modified polytetrafluoroethylene resin (A) which is composed of tetrafluoroethylene and a trace amount of a monomer. The weld covering material is placed on a joint part of a resin matrix composed of polytetrafluoroethylene resin (B) and welding is executed so that the joint part of the resin matrix is covered with the weld covering material. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【００７８】
【表２】

【００７９】
【表３】

【００８０】
【表４】

【００８１】
【表５】

【００８２】
【表６】

【００８３】
【表７】

【００８４】
以上の表から、（溶接）被覆材の原料として変性ＰＴＦＥ樹脂を用いた実施例１〜５は、何れも洩出部は生じないことがわかったが、（溶接）被覆材の原料としてＰＦＡを用いた比較例２では、図５に示すような洩出部５１が生じ、これを除去する際、（樹脂）母材部の溶接端部５２まで傷つけてしまうことがわかった。また、（溶接）被覆材の原料として（樹脂）母材よりも溶融粘度の低い変性ＰＴＦＥ樹脂を用いた表２の実施例２〜５は、（溶接）被覆材の原料としてＴＦＥホモポリマーを用いた比較例１又は（溶接）被覆材の原料としてＰＦＡを用いた比較例２に比べて、溶接状態が良好であることがわかった。
【００８５】
参考例１ プライマーを用いた容器の薬液曝露試験
母材としてポリテトラフルオロエチレン樹脂からなる厚さ３ｍｍのシート、被覆材として比較例２で用いたＰＦＡを用い、プライマー（乳化重合により得られたＰＦＡを界面活性剤等により分散安定化したディスパージョン）を介して比較例２と同じ条件で溶接し、接合体を得た。
得られた接合体を硫酸及びオゾンに温度１２０℃で２か月間曝露し、走査型電子顕微鏡〔ＳＥＭ〕を用いて観察したところ、図４に示すように、母材部と被覆部との境界等に、ダストが発生していることがわかった。
得られたＳＥＭ画像をもとに、ダストカウンターを用いて、母材部と被覆部との境界部体積１ｍｌ当たりに含まれる平均粒子径０．２μｍ以上のダストの個数を観察したところ、１５個／ｍｌであった。また、実施例１と同様に溶接部伸びと引っ張り強度とを測定したところ、上記曝露前に比べて、溶接部の引っ張り強度は２０％低下し、伸びも３５％低下した。ついで、質量分析計を用いて黒色部の元素分析を行った結果、フッ素含有量が黒色に変化しなかった通常部の５０％以下に低下したことがわかった。

以上の結果から、ＳＥＭにより観察されたダストは、プライマー中に含まれる界面活性剤の炭化により遊離浮遊異物を発生したことによるものと推定された。
【００８６】
【発明の効果】
本発明の溶接被覆材及び溶接施工方法は、上述の構成よりなるので、溶接後、樹脂母材の接合部の薬液透過が少なく、溶接信頼性に優れ、かつ、洩出部を生じていない溶接施工品を提供することができる。
【図面の簡単な説明】
【図１】図１は、溶接強度及び伸びを測定するサンプルの模式的上面図及び模式的断面図である。
【図２】図２は、比重測定用サンプルの採取部位を示す模式的断面図である。
【図３】図３は、溶接の工程を示す模式的断面図である。
【図４】図４は、参考例１における溶接部のＳＥＭ像である。
【図５】図５は、洩出部及び溶接端部の模式的断面図である。
【符号の説明】
１１ 溶接被覆部
１２ 樹脂母材部
２１ 溶接被覆部（比重測定用）
２２ 溶接周辺部
２３ 開先凹部
３１ 溶接被覆材
３２ 樹脂母材
３３ 熱風
３４ 加圧
３５ 溶接走行
５１ 洩出部
５２ 溶接端部[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a welding covering material, a joint structure, a welding method, a welding product, and a composite article.
[0002]
[Prior art]
BACKGROUND ART Articles requiring corrosion resistance, such as metal can bodies and piping materials, are lined with a resin having chemical resistance and solvent resistance. Conventionally, lining has been performed not by coating but by sheet lining since low chemical solution permeability is required. In sheet lining, a sheet material is used to cover inner walls of a can body, a piping material and the like.
[0003]
As a sheet material, a fluororesin is generally used. Among them, polytetrafluoroethylene [PTFE] resin has extremely low metal contained in the resin itself and little metal elution. It is suitably used as a sheet material for semiconductor-related containers that have high demands.
[0004]
Sea lining requires welding sheet seams. As a method of the welding, a method was considered in which the sheets were overlapped at the seam portion, and the overlapped portions were thermocompression-bonded from above and below. However, bonding between sheets made of a homopolymer of tetrafluoroethylene [TFE homopolymer] was considered. There was a problem that it was difficult.
[0005]
In order to adhere the sheets, a method using a modified polytetrafluoroethylene [modified PTFE] resin for at least one of the superposed sheets (for example, see Patent Document 1), and a method for fusing PTFE sheets are described below. A method has been proposed in which a tetrafluoroethylene / perfluoro (alkylvinyl) ether copolymer [PFA] film is interposed therebetween and fused (for example, see Patent Documents 2 and 3).
However, each of the above methods is a method of heat fusion, and it is necessary to heat the entire fusion portion, and there is a problem of an increase in welding time and a decrease in productivity. Further, the lining of the can body and the piping material has a problem that one side of the sheet is in contact with the inner wall of the can body and the piping material, and it is impractical to apply pressure from both sides of the sheet.
[0006]
As a method of bonding the sheets, both ends of the sheet serving as a seam are cut and grooved and butted, a welding rod made of PFA is buried in the groove, and PFA is further formed on the obtained sheet joint. A method of thermally welding a welding cladding material such as a reinforcing ribbon has been devised.
[0007]
A method using a PTFE polymer as a sheet is known as a method of using a welding covering material made of PFA. However, in order to obtain stable adhesiveness, a welding portion is previously provided between a sheet joint and a welding covering material. (See, for example, Patent Documents 4, 5, 6, and 7) and the like, which are currently in use.
[0008]
However, in the method using a primer, it is difficult to control the coating thickness, there is a problem that welding reliability is reduced due to uneven coating, and a surfactant is used for stabilizing the primer. When exposed to chemicals having a strong oxidizing power as used in the above, there is a problem that the surfactant causes dust.
[0009]
In the method using a PFA welding coating, pressure is applied to weld the sheet joint and the welding coating. At this time, the molten welding coating is applied from the boundary between the welding coating and the sheet. There is a problem of forming a protruding leak portion. Since the leaked portion is not pressurized during the welding process, there is a problem that cracks are generated due to crystallization shrinkage during cooling after welding. In particular, when lining can bodies, piping materials, and the like in the semiconductor industry and the like, there is a problem in that foreign matter attached to the leaked portion becomes dust.
[0010]
It is necessary to cut off the leaked portion at the boundary between the sheet and the welding coating material, but at this time, there is a possibility that the sheet may be damaged. If the sheet is scratched, the boundary is hardly stretched when concentrated stress is applied, and voids are likely to occur due to partial elongation at the weld boundary when performing stretching such as flange processing, and the chemical solution permeates from the void. There was a problem that occurs.
[0011]
In recent years, resin base materials with higher specific gravity than conventional ones have been developed, and although some reduction has been seen in the decrease in chemical permeability, a high degree of cleanliness has been achieved with the super-integration and high density of semiconductor circuits. In order to avoid corrosion of inner walls of can bodies and piping materials and elution of metal from lining materials, higher chemical liquid permeability is being demanded.
[0012]
[Patent Document 1]
JP-B-56-36064
[Patent Document 2]
JP-A-52-63274
[Patent Document 3]
JP-A-52-63275
[Patent Document 4]
JP-A-59-120417
[Patent Document 5]
JP-A-57-163524
[Patent Document 6]
JP-A-57-142246
[Patent Document 7]
JP-A-59-33331
[0013]
[Problems to be solved by the invention]
The present invention has been made in view of the above-mentioned circumstances, and provides a weld coating material having a small chemical solution permeation at a sheet joint portion, having excellent welding reliability, and having no leakage portion, and covering the base material with the weld coating material. An object of the present invention is to provide a welding method.
[0014]
[Means for Solving the Problems]
The present invention relates to a welding covering material made of a modified polytetrafluoroethylene resin (A), wherein the welding covering material is placed on a joint of a resin base material made of a polytetrafluoroethylene resin (B). The modified polytetrafluoroethylene resin (A) is for covering a joint portion of the resin base material by performing welding, and the modified polytetrafluoroethylene resin (A) is composed of tetrafluoroethylene and a trace amount of monomer. It is a welding covering material.
[0015]
The present invention is a joining structure comprising a joining portion of a resin base material made of a polytetrafluoroethylene resin (B) and the above-mentioned welding covering material, wherein the welding covering material is provided on the joining portion of the above-mentioned resin base material. The modified polytetrafluoroethylene resin (A) is obtained by placing and welding, and the modified polytetrafluoroethylene resin (A) is composed of tetrafluoroethylene and a trace amount of monomer. is there.
The present invention is a welded product having the above-mentioned joint structure.
[0016]
The present invention is a welding method comprising placing the above-mentioned welding coating material on a joint portion of a resin base material made of polytetrafluoroethylene resin (B) and welding the welding coating material. It is a welding construction method characterized by comprising a tetrafluoroethylene resin (A).
Hereinafter, the present invention will be described in detail.
[0017]
The weld coating material of the present invention is composed of a modified polytetrafluoroethylene resin (A).
The modified polytetrafluoroethylene resin (A) is composed of tetrafluoroethylene [TFE] and a trace amount of monomer. That is, the modified polytetrafluoroethylene resin (A) is a resin composed of a copolymer composed of TFE and a trace amount of monomer.
The trace monomer is used for the trace copolymer to the extent that the obtained copolymer does not impart melt flowability.
[0018]
The above-mentioned trace monomer is not particularly limited as long as it is capable of copolymerizing with TFE and does not impart melt flowability to the obtained copolymer. For example, hexafluoropropylene [HFP] and the like Perfluoroolefins; chlorofluoroolefins such as chlorotrifluoroethylene; hydrogen-containing fluoroolefins such as trifluoroethylene; and perfluorovinyl ether.
[0019]
The perfluorovinyl ether is not particularly limited, for example, the following general formula
CF₂= CF-ORf
(In the formula, Rf represents a perfluoro organic group.) And the like. In the present specification, the “perfluoro organic group” means an organic group in which all hydrogen atoms bonded to carbon atoms are replaced by fluorine atoms. The perfluoro organic group may have ether oxygen.
[0020]
Examples of the perfluorovinyl ether include perfluoro (alkylvinyl) ether [PAVE] in which Rf represents a perfluoroalkyl group having 1 to 10 carbon atoms in the above general formula. The perfluoroalkyl group preferably has 1 to 6 carbon atoms.
[0021]
Examples of the perfluoroalkyl group in the above PAVE include a perfluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluorobutyl group, a perfluoropentyl group, a perfluorohexyl group, and the like. Groups are preferred.
Preferably, the trace monomer is PAVE and / or HFP.
[0022]
The modified polytetrafluoroethylene resin (A) contains 0.05 to 0.7% by mass of a copolymer in which the trace monomer units derived from the trace monomer are TFE and the trace monomer. Some are preferred. When the content is less than 0.05% by mass, the obtained weld coating material may have poor adhesion to a resin base material described later. When the content exceeds 0.7% by mass, the specific gravity of a weld coating portion described later tends to decrease, and the chemical liquid permeability may increase.
In the present specification, the above-mentioned trace monomer unit is a part on the polymer molecular structure of the modified polytetrafluoroethylene resin (A), and means a part derived from the trace monomer.
[0023]
As the modified polytetrafluoroethylene resin (A), for example, one or more copolymers having different molecular weight distributions, copolymer compositions, and the like may be used.
The number average molecular weight of the copolymer of the modified polytetrafluoroethylene resin (A) is such that the amount of the trace monomer unit is in the above-mentioned range, and the melt viscosity is in the range described later, that is, 1 × 10⁸~ 15 × 10⁸It is defined as being in the range of Pa · s, and usually preferably in the range of 200,000 to 20,000,000. When the number average molecular weight is within the above range, the mechanical strength of the welded coating part in the obtained joint structure described later will be good. A more preferred lower limit is 1.8 million, and a still more preferred lower limit is 6.30 million.
[0024]
The polymerization method for obtaining the modified polytetrafluoroethylene resin (A) is not particularly limited, and includes, for example, conventionally known polymerization methods such as emulsion polymerization and suspension polymerization.
The above-mentioned welding coating material is obtained by subjecting the modified polytetrafluoroethylene resin (A) after polymerization to powder obtained by subjecting the modified polytetrafluoroethylene resin (A) to pulverization, granulation, or the like as required, such as ram extrusion molding, paste extrusion molding, compression molding, or the like. It may be obtained by molding by a conventionally known molding method, or may be obtained by cutting a molded body.
[0025]
The above welding coating material has a melt viscosity of 1 × 10⁸~ 15 × 10⁸It is preferably Pa · s. When the melt viscosity is within the above-mentioned range, it is possible to suppress the formation of a leak portion described later, though the shape is slightly deformed during welding and pressurization. In order to obtain a weld coating material having a melt viscosity within the above range, usually, a modified polytetrafluoroethylene resin (A) having a melt viscosity within the above range is used.
The melt viscosity η was measured using a dynamic viscoelasticity measuring device (trade name: PDS-II, manufactured by Rheometrics).
[0026]
The weld coating material of the present invention is for covering the above-mentioned joint portion of the resin base material by placing it on the joint portion of the resin base material and performing welding.
The above-mentioned welding covering material has a shape capable of covering a joint portion of a resin base material described later, and may be a material having a sufficient thickness to reduce chemical liquid permeability, and is usually in a ribbon shape or a strip shape. , And a band shape.
[0027]
In this specification, the above-mentioned resin base material means a resin molded article to be covered with the above-mentioned welding covering material placed on a joint. The resin base material has a size suitable for being partially or entirely covered with the welding coating material. However, limitations such as the thickness, size, and the like must be larger than the welding coating material are given below. Absent. The shape of the resin base material is not particularly limited, and may be, for example, a block shape, a sheet shape, or the like. Among them, a sheet shape is preferable, and a lining sheet base material is more preferable.
[0028]
The lining sheet base material is a sheet-shaped resin base material that can be used as a lining material for coating a base material. The lining material covers the base material in a sheet lining, thereby imparting corrosion resistance, protecting the base material such as improving mechanical strength, imparting non-adhesiveness, and smoothing the surface. Those exhibiting an action of improving the surface properties of the material, an action of improving the appearance of the base material, and the like are included.
The base material is not particularly limited, but is generally preferable or required to exhibit the effect of the lining material.Examples of the material include stainless steel, copper, aluminum, bronze, zinc, brass, and titanium. Metal; glass and the like.
[0029]
The lining sheet base material may be used as it is without cutting the resin molded body, but is generally manufactured by cutting from a large block-shaped resin molded body. The lining sheet base material may be formed by applying an appropriate surface treatment or laminating a heat-resistant nonwoven fabric or a heat-resistant woven fabric such as a glass cloth in order to adhere to the base material.
[0030]
The resin base material is made of a polytetrafluoroethylene resin (B). The polytetrafluoroethylene resin (B) may be a tetrafluoroethylene homopolymer [TFE homopolymer] resin obtained by polymerizing TFE alone, or may be a modified resin comprising TFE and the above-mentioned trace monomer. Although the polytetrafluoroethylene resin (B1) may be used, the modified polytetrafluoroethylene resin (B1) may be modified in that a primer does not need to be used when welding the above-mentioned welding coating material composed of the modified polytetrafluoroethylene resin (A). Preferably, it is an ethylene resin (B1).
[0031]
The modified polytetrafluoroethylene resin (B1) is the same modified polytetrafluoroethylene resin as the above-described modified polytetrafluoroethylene resin (A), but is different from the above-described welding in that it is used for the resin base material. It is conceptually different from the modified polytetrafluoroethylene resin (A) used for the coating material. The copolymer of the modified polytetrafluoroethylene resin (B1) has the copolymer of the modified polytetrafluoroethylene resin (A) and the kind of the trace monomer, the ratio of the trace monomer unit, the molecular weight distribution and the like. Although they may be the same or different, they are preferably substantially the same in terms of adhesiveness.
The resin base material may be composed of additives and the like in addition to the resin component. The resin component is preferably the polytetrafluoroethylene resin (B), and may be only the polytetrafluoroethylene resin (B).
[0032]
In the present specification, the “joined portion of the resin base material” means a portion of the resin base material formed by joining the ends.
In the present specification, the term “joining” means at least sticking or joining to such an extent that they cannot be separated without mechanical cutting. The above-mentioned “joining” usually means that the above-mentioned resin base material and a welding auxiliary material to be used later, which are used as desired, are bonded together by fusion or in a state thereof.
[0033]
The joining portion of the resin base material is formed by abutting and directly contacting resin base materials having the same or different shapes, sizes, etc., and placing the resin base material under pressure at a temperature equal to or higher than the melting point of the polytetrafluoroethylene resin (B). The base material may be joined to each other, or the resin base materials having the same or different shapes, sizes, etc., may be interposed between welding bases or primers, which are welding aids to be described later. What indirectly joined between them may be used.
[0034]
The joint portion of the resin base material may be formed by abutting two resin base materials as a groove and filling a recess formed by the two resin base materials with a welding rod. The welding rod will be described later. The joining portion of the resin base material may be, for example, one obtained by joining both ends of a sheet-like resin base material such as one lining sheet base material, or one obtained by joining two resin base materials together. It may be. The joint portion of the resin base material is usually a part of the resin base material. However, since the resin base material is to be covered with the welding coating material as described above, the resin base material is When the size is almost the same as the size of the welding covering material, it may indicate the entire resin base material.
[0035]
In the present specification, the term "place on the joint" means to put the weld coating material on the joint of the resin base material. When the resin matrix is composed of the TFE homopolymer resin, it is necessary to mediate a primer described below between the resin matrix and the weld coating material. When it is made of a fluoroethylene resin (B1), the primer does not need to be interposed because it has excellent compatibility with the modified polytetrafluoroethylene resin (A) in the weld coating material.
In the present specification, the above-mentioned “welding” means that a joint portion of the resin base material and the weld coating material are fused.
In the present specification, the “welding” refers to fusing the joint portion of the resin base material and the weld coating material, whereas the “joining” at the joint portion of the resin base material is as described above. In addition, the two are different concepts in that the resin base materials having the same or different shapes or sizes are fused.
[0036]
The joined structure of the present invention comprises a welded coating made of the modified polytetrafluoroethylene resin (A) and a joined part of a resin base material made of the polytetrafluoroethylene resin (B). This is obtained by placing the above-mentioned welding covering material on the joint portion of the resin base material and performing welding.
[0037]
The joint structure includes a weld coating portion derived from the weld coating material and a resin base material portion described below derived from the resin base material.
In the present specification, the term "weld coating portion" means a portion derived from a welding coating material after welding in the joint structure. The above-mentioned weld coating portion may have undergone welding, and may have a change in crystallinity or the like before this heating due to heating during welding, and may have changed the specific gravity as a result. In this respect, the concept is different from that of a weld coating material that has not been subjected to welding.
In the present specification, the “resin base material portion” means a portion derived from the resin base material after performing the welding, including a portion affected by heating during welding in the joint structure. I do. Since the resin base material portion includes the portion affected by heating during welding, the resin base material portion includes at least a portion existing under the weld coating portion, and the resin base material after welding is performed. Since it is a portion derived from the material, the vertical portion sandwiched between the contact surface and the back surface of the welded coating material to be placed among the horizontal portions of the resin base material to be present below the weld coating portion. It is derived from the direction part.
The above-mentioned resin base material portion has been subjected to welding, and may have a degree of crystallinity or the like before heating due to heating during welding, and may have a specific gravity changed as a result. In a good point, it is a concept different from a resin base material which has not been subjected to welding.
[0038]
As described above, the modified polytetrafluoroethylene resin (A) is a copolymer in which the trace monomer unit derived from the trace monomer is composed of TFE and the trace monomer. It is preferably 7% by mass.
In applications where a high degree of low chemical liquid permeability is required, the modified polytetrafluoroethylene resin (A) can be used in the joint structure of the present invention because the trace monomer unit is composed of TFE and the trace monomer. And the specific gravity of the weld coating portion is preferably from 2.145 to 2.210.
In the modified polytetrafluoroethylene resin (A), when the above-mentioned trace monomer unit is 0.05 to 0.5% by mass of the copolymer of TFE and the trace monomer, the specific gravity of the weld coating portion Can be increased, and the specific gravity of the weld coating portion can be easily set to 2.145 to 2.210. When the specific gravity is within the above range, the bonded structure of the present invention has a high low chemical solution permeability.
[0039]
The specific gravity of the weld coating portion is a value obtained by cutting out a sample in accordance with JIS K 7137-2 and measuring the sample in accordance with JIS K 7112-A method (submersion method). However, when the resin base material is formed by laminating a heat-resistant nonwoven fabric or a heat-resistant woven fabric such as a glass cloth, the specific gravity is measured after peeling the heat-resistant nonwoven fabric or the heat-resistant woven fabric.
[0040]
In obtaining the joined structure of the present invention, the melt viscosity (a) of the weld coating material is 1 × 10⁸~ 15 × 10⁸Pa · s is preferable (condition (1)), and the melt viscosity (a) is preferably equal to or lower than the melt viscosity (b) of the resin base material (condition (2)).
The joint structure of the present invention is such that the welding coating used is made of the modified polytetrafluoroethylene resin (A) and the melt viscosity of the welding coating used satisfies the above conditions (1) and (2). Thus, excellent welding reliability can be obtained. The joint structure of the present invention has welding reliability, and in order to further ensure low chemical liquid permeability, the crystallinity of the weld coating portion and the resin base material portion is increased, and the specific gravity is increased. Is preferred.
With the above welding reliability, the welding coating material and the resin base material are fused together on the entire surface where they come into contact, and when the welding reliability is lost, the chemical solution, the gas, etc. in the presence of a chemical solution, a highly reactive gas, etc. May penetrate through a gap between the weld coating and the resin base material.
[0041]
It is generally considered that the melt viscosity does not change before and after welding. Therefore, the above condition (1), or the above conditions (1) and (2) were satisfied before welding, Can be confirmed by measuring the melt viscosity of the weld coating portion and the melt viscosity of the resin base material portion of the joint structure of the present invention. Therefore, the joint structure of the present invention has a melt viscosity of 1 × 10⁸~ 15 × 10⁸Pa · s is preferable, and the melt viscosity of the weld coating portion is more preferably within the above range and not more than the melt viscosity of the resin base material portion.
[0042]
As described above, the polytetrafluoroethylene resin (B) in the resin base material used to obtain the joint structure of the present invention is a modified polytetrafluoroethylene resin (B1) composed of TFE and a trace amount of monomer. Is preferred. When the modified polytetrafluoroethylene resin (B1) is used as the resin base material, the joint structure of the present invention has sufficient adhesiveness even if no primer is used between the resin base material and the weld coating material. Can be provided.
In the present specification, the “primer” is a welding auxiliary material used for improving the adhesiveness between the resin base material portion and the weld coating portion, and is a liquid such as a dispersion at the time of application. is there.
[0043]
The primer is made of a perfluoro resin (C). The primer is usually a dispersion of particles of the perfluororesin (C) dispersed in water, an organic medium or a mixture of water and an organic medium, which is dispersion-stabilized with a surfactant or the like. It is.
The perfluoro resin (C) has a melt viscosity of 1 × 10^FiveIt is a resin of Pa · s or less and a resin composed of a polymer molecule in which all of the hydrogen atoms bonded to carbon atoms are substituted with fluorine atoms, and among them, a perfluoroolefin resin is preferable.
In the present specification, the “perfluoroolefin resin” means a resin composed of a polymer obtained by polymerizing at least one kind of perfluoroolefin and, if desired, PAVE.
The perfluoroolefin resin is not particularly limited, and examples thereof include a resin composed of a TFE / HFP copolymer and a resin composed of a TFE / PAVE copolymer.
[0044]
It is preferable that the joining structure of the present invention does not use a primer between the resin base material and the above-mentioned welding covering material. If the bonding structure of the present invention does not use a primer, the surfactant contained in the primer may be exposed to a chemical having a strong oxidizing power and carbonized to become a dust generation source. Absent.
[0045]
In the present specification, the phrase "no primer is used between the resin base material and the weld coating material" means that the resin base material is used when the joint structure of the present invention is obtained from the resin base material and the weld coating material. Means that the primer was not interposed at any point between the above and the welding covering material.
[0046]
The use of a primer between the above "between the resin base material and the welding coating material" means that (i) the primer is applied on the surface of the joint portion of the resin base material on which the welding coating material is to be mounted. And (ii) applying a primer to a surface of the weld coating material that is to be placed on the joint of the resin base material. In the case where the joint portion of the resin base material is one in which two resin base materials are grooved and butted as described later, and a recess formed thereby is filled with a welding rod, the above (i) is formed with a groove. A primer is applied to the surface of the two resin base materials to be in contact with the welding rod to be filled ((i) -1), and the resin base material obtained by filling the welding rod is The method includes (i) -2 applying a primer on a surface of the joint portion on which the welding coating material is to be placed.
In the above ((i) -2), the “surface on which the welding coating material is to be mounted” is the surface on which the welding coating material is to be mounted on the portion derived from the filled welding rod. And a surface on which the welding rod melted and solidified by filling is not attached to the resin base material and on which the welding coating material is to be placed.
[0047]
In the joint structure of the present invention, the resin base material before welding is preferably the lining sheet base material described above. When the base material is a lining sheet base material, the joining structure is excellent in low chemical liquid permeability as described above, and thus is suitable for a lining material.
[0048]
The joint structure of the present invention may be one in which no leak portion exists.
The above “leakage portion” means a portion generated by protruding from between the welded coating material and the joint portion of the resin base material in the process of pressure-melting the welding coating material in welding. The above-mentioned leaking portion is generally referred to as a “protruding portion” or “burr” in that the resin melted by heating is generated by protruding from a target contour of the resin molded body after heating and melting. Including concepts common to
[0049]
The above-mentioned joint structure uses a modified polytetrafluoroethylene resin (A) as a material for the welding coating material, and since it is difficult for a leaked portion to occur even when welding is performed, a leaked portion is conventionally generated. Therefore, there is no need to perform the necessary removal processing of the leaked part. If there is no need to perform the removal processing, there is no possibility of damaging the joint structure, and there is no fear that cracks will occur. The removal process is generally performed by cutting or the like using an instrument such as a chisel V-shaped chisel.
[0050]
According to the welding method of the present invention, a welding covering material made of the modified polytetrafluoroethylene resin (A) is placed on a joint of a resin base material made of the polytetrafluoroethylene resin (B) and welded. Is performed.
The above-mentioned "modified polytetrafluoroethylene resin (A)", "weld coating material", "polytetrafluoroethylene resin (B)", "joined portion of resin base material", "placed on the joined portion", and "welding" Is as described above.
[0051]
In the welding construction method of the present invention, it is preferable that the joint portion of the resin base material is formed by abutting two resin base materials with a groove and filling a recess formed by the groove with a welding rod.
The welding rod is a welding auxiliary material mainly used for bonding between the two resin base materials by being interposed between the concave portions, that is, the two resin base materials. It is a solid prior to heating during the process. The welding rod not only bonds between the two resin base materials, but also contributes to bonding with a welding covering material usually placed on the filled portion. The welding rod may be one that is generally recognized as a welding rod in the field of welding a resin molded product.
[0052]
The welding rod is made of a perfluoro resin (D), and the perfluoro resin (D) has a melt viscosity of 1 × 10^FiveIt is preferably at most Pa · s. A more preferred upper limit of the melt viscosity is 0.4 × 10^FivePa · s.
The perfluoro resin (D) may be a resin composed of a polymer molecule in which all of the hydrogen atoms bonded to carbon atoms are substituted with fluorine atoms, and among them, a perfluoroolefin resin is preferable. The perfluoroolefin resin is the same as described above for the perfluororesin (C).
The perfluoroolefin resin is not particularly limited, and includes, for example, a resin composed of a TFE / PAVE copolymer, a resin composed of a TFE / HFP copolymer, and the like.
[0053]
The perfluoro resin (D) is a resin used for a welding rod, and is conceptually different from the above-mentioned perfluoro resin (C) which is a resin used for a primer between a resin base material and a welding covering material. Are different. The molecular weight distribution of the polymer in the perfluoro resin (D), the type of the monomer, and the like may be the same as or different from the perfluoro resin (C).
[0054]
The filling of the concave portion of the welding rod is performed by applying a pressure of 0.3 to 2.5 MPa at a welding speed of 70 to 200 mm / min while heating the welding rod to a welding temperature of 460 to 550 ° C. Is preferred. The welding temperature to be employed depends on the air volume and welding speed. For example, if the welding speed is less than 70 mm / min at 550 ° C., which is the upper limit of the welding temperature, the polytetrafluoroethylene resin (B) constituting the resin base material and the modified polytetrafluoroethylene constituting the welding coating material The ethylene resin (A) may decompose together. Therefore, it is preferable to perform welding under the condition that the values of the welding temperature, the welding speed and the pressure are all within the above ranges.
In the above-described joint portion of the resin base material, the portion that overflows from the groove by filling the welding rod into the concave portion forms a raised portion (convex portion) after cooling, which hinders welding of the welding coating material. There is. Therefore, it is desirable that the joint portion of the resin base material is obtained by flattening the convex portion with a chisel or the like.
[0055]
In the welding method according to the present invention, the resin base material is preferably a lining sheet base material. When a lining sheet base material is used as the resin base material, the welding construction method of the present invention is suitable in that the obtained joint structure can realize a high degree of low chemical liquid permeability. In the welding construction method of the present invention, in the case where the resin base material is a lining sheet base material, the welding is performed by heating such that a contact surface between a joint portion of the resin base material and a welding covering material is at 520 to 620 ° C. It is more preferable that the welding is performed by applying a pressure of 0.3 to 2.5 MPa at a welding speed of 30 to 140 mm / min.
[0056]
In the case where the resin base material is made of a resin molded body having the same or different shape, size, and the like, and is other than the lining sheet base material, for example, a block-shaped molded body, the welding is performed by joining the resin base material. It is more preferable that the heating is performed such that the contact surface between the portion and the welding coating material is at 520 to 620 ° C. and a pressure of 0.3 to 5 MPa is applied.
[0057]
Cooling after performing the above welding, by increasing the crystallinity of the resin base material portion and the weld coating portion in the obtained joint structure, increasing the specific gravity, can reduce the chemical liquid permeability, by slow cooling, It is preferably performed, and more preferably performed by air cooling.
[0058]
As described above, the modified polytetrafluoroethylene resin (A) in the welding coating material used in the welding construction method of the present invention is such that the trace monomer unit derived from the trace monomer is composed of TFE and the trace monomer. Is preferably 0.05 to 0.7% by mass of the copolymer consisting of
In applications where a high degree of low chemical liquid permeability is required, the above-mentioned trace monomer unit derived from the trace monomer of the modified polytetrafluoroethylene resin (A) is a copolymer comprising TFE and the trace monomer. More preferably, it is 0.05 to 0.5% by mass of the coalescence.
[0059]
The resin base material used in the welding construction method of the present invention preferably has a specific gravity of 2.175 to 2.200. When the specific gravity is within the above range, the specific gravity of the resin base material after welding is likely to be high, and the chemical liquid permeability is easily suppressed. The resin base material has a trace monomer unit in the above-mentioned copolymer of the modified polytetrafluoroethylene resin (B1) exceeding 0.5% by mass of the copolymer composed of TFE and the trace monomer. In some cases, the specific gravity tends to be less than 2.175.
[0060]
The trace monomer in the modified polytetrafluoroethylene resin (A) used for the welding coating material in the welding construction method of the present invention, and the trace monomer in the modified polytetrafluoroethylene resin (B1) used for the resin base material are: As described above, PAVE and / or HFP are preferred.
As described above, the welding cladding material used in the welding construction method of the present invention has (1) a melt viscosity (a) of 1 × 10⁸~ 15 × 10⁸Pa.s is preferable, and (2) the melt viscosity (a) is more preferably equal to or less than the melt viscosity (b) of the resin base material. If the melt viscosity satisfies the above conditions (1) and (2), welding with reliable welding can be performed.
[0061]
As described above, it is preferable that the welding covering material is placed on the joint portion of the resin base material without using a primer on the resin base material. The primer is made of the above-mentioned perfluoro resin (C), and the perfluoro resin (C) has a melt viscosity of 1 × 10^FivePa · s or less.
Since the above welding method uses the welding covering material made of the above-mentioned modified polytetrafluoroethylene resin (A), it is possible to prevent a leak portion from being generated.
[0062]
ADVANTAGE OF THE INVENTION By the welding construction method of this invention, the adhesiveness of a welding covering part and a resin base material part can be improved, and the durability and corrosion resistance of the joining structure obtained can be improved. According to the welding method of the present invention, it is also possible to increase the specific gravity of the weld coating portion and the resin base material portion. In recent years, a resin base material having a high specific gravity has been developed. It is possible to realize a high degree of low chemical solution permeability that could not be achieved only by chemical conversion.
[0063]
The present invention also relates to a joint structure including a joint portion of a resin base material and a welding covering material, which is obtained by the above-described welding method.
A welded product of the present invention has the above-mentioned joint structure. The joint structure is composed of the joint portion of the weld coating material and the resin base material as described above, and the welded product is obtained by welding the resin base material with the weld coating material. It is. The welded product is composed of the joint structure and a portion of the resin base material other than the resin base material portion that forms the joint structure. As described above, when the resin base material is small in size to such an extent that the entire resin base material is affected by heating at the time of welding, the resin base material itself becomes the resin base material portion constituting the joint structure. The welded product is the joint structure itself.
[0064]
In the welded product of the present invention, the resin base material is preferably a lining sheet base material. In the present specification, the above-mentioned "welded article in which the resin base material is the lining sheet base material" is referred to as "weld lining material". In the present specification, the welding lining material does not include a base material.
[0065]
The composite article of the present invention comprises a base material and the above-mentioned welded product.
The base material is a target to be covered by a welding product such as the welding lining material, and examples thereof include those described above as being covered by the lining sheet base material.
The size of the composite article is not particularly limited, and may be one used on a plant scale or one used on a laboratory scale.
The composite article is not particularly limited and includes, for example, chemical reaction members such as containers, tanks, tanks, towers, piping materials, joints, and stirring blades. In the composite article, the base material may be in close contact with the welded product, or the base material and the welded product may simply be in contact with each other, and may be easily separable. Good, but it is preferable that they are closely adhered.
The composite article is one in which all or a part of one surface of the base material or all or a part of both surfaces of the base material is coated with the welded product. In the case where the composite article is made of a lining sheet base material, the welded article is formed of a lining sheet base material, and at least a portion of the surface of the base material where the action of the lining material is preferable or required is preferably a lining sheet base material. What is necessary is just what was covered with.
[0066]
The use of the composite article is not particularly limited. For example, a corrosive or oxidizing chlorine exposure apparatus in which dry chlorine and wet chlorine coexist in the food electrolysis industry, etc .;_ThreeAbsorption tower; Equipment for producing inorganic acids such as hydrogen peroxide, hypochlorous acid, sulfuric acid, nitric acid, hydrochloric acid, hydrofluoric acid, etc., which are highly oxidizable and cannot withstand long-term use with rubber or FRP; Examples include a semiconductor manufacturing apparatus for storing or transporting a chemical solution such as hydrofluoric acid used for washing or the like, among which a semiconductor manufacturing apparatus is preferable.
Among the composite articles of the present invention, examples of the above-mentioned "object used in a semiconductor manufacturing apparatus" include a pipe member in contact with a chemical such as hydrofluoric acid, a joint member of the pipe member, a member such as a storage tank, and the like.
[0067]
【Example】
Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.
Example 1
As a raw material of the welding coating material, a modified PTFE resin powder (melt viscosity of 13 × 10⁸Pa · s, standard specific gravity 2.145). To 100 parts by mass of the modified PTFE resin powder, 20 parts by mass of a petroleum-based solvent (trade name: Isopar E, manufactured by Exxon Chemical Co., Ltd.) was added and mixed, and paste extrusion was performed. After the petroleum-based solvent was dried and removed at 100 ° C to 200 ° C, it was baked at 370 ° C for 1 to 10 minutes to obtain a weld coating material. The specific gravity of the obtained weld coating material was 2.149.
A welding rod made of a TFE / PAVE copolymer is blown with hot air of 480 ° C. on the groove recess 23 of the resin base material in the schematic sectional view of FIG. 2 while applying a pressure of 0.3 to 0.5 MPa. Filling was performed at a welding speed of 125 mm / min, and the resin base materials were bonded to each other. As shown in the schematic cross-sectional view of FIG. 3, the above-mentioned welding covering material is placed on the joint portion of the obtained resin base material, and hot air 33 having a temperature of 580 ° C. is blown thereon. The welding traveling 35 was performed at a welding speed of 125 mm / min while applying a pressure of 0.5 MPa to obtain a joined structure.
[0068]
The following evaluation was performed on the obtained joined structure.
Weld elongation and tensile strength
As shown in the schematic top view and the schematic cross-sectional view of FIG. 1, a sample having a width of 10 mm and a length of 100 mm including the weld coating portion 11 and the resin base material portion 12 was cut out from the obtained joint structure. A reference point was provided at a distance of 40 mm on the resin base material portion of the obtained sample, and the following formula was used.
Elongation of weld (%) = [{Distance between gauge points at maximum elongation (mm) -40 mm} / 40 mm] × 100
And the tensile strength was measured at the same time.
Welding condition
Good welding: A state in which the variation in the elongation and tensile strength of the welded portion is small, and no unfused portions are observed in the cross section of the joined structure.
Unreliable: A condition where the elongation and tensile strength of the weld vary depending on the sample, and unfused portions are observed on the cross section of the joined structure.
Welding is impossible. There is almost no elongation and tensile strength at the weld, and unfused parts are observed on the cross section of the joined structure.
[0069]
Specific gravity of weld coating and weld periphery
As shown in the schematic cross-sectional view of FIG. 2, a specific gravity measurement sample is cut out from the weld coating portion 21 and the welding peripheral portion 22 that is a part of the resin base material portion in accordance with JIS K 7137-2. The specific gravity was measured based on 7112-A (underwater displacement method).
However, the specific gravity of the glass cloth backing sheet was measured after peeling the glass cloth.
[0070]
Example 2
The modified PTFE resin powder shown in Table 1 was used as a raw material of the weld coating material. The above-mentioned raw material was filled in a mold and pressurized at 30 MPa, a preform was obtained, and the preform was fired at 370 ° C. for 10 hours, and then skived to obtain a weld coating material. The specific gravity of the obtained weld coating material was 2.195. This weld coating material was welded to the resin base material under the welding conditions shown in Table 1, and the obtained joint structure was evaluated in the same manner as in Example 1.
[0071]
Example 3
The modified PTFE resin powder shown in Table 1 was used as a raw material of the weld coating material. The above-mentioned raw material was filled in a mold and pressurized at 30 MPa, a preform was obtained, and the preform was fired at 370 ° C. for 10 hours, and then skived to obtain a weld coating material. The specific gravity of the obtained weld coating material was 2.152. This weld coating material was welded to the resin base material under the welding conditions shown in Table 1, and the obtained joint structure was evaluated in the same manner as in Example 1.
[0072]
Example 4
The modified PTFE resin powder shown in Table 1 was used as a raw material of the weld coating material. The above-mentioned raw material was filled in a mold and pressurized at 30 MPa, a preform was obtained, and the preform was fired at 370 ° C. for 10 hours, and then skived to obtain a weld coating material. The specific gravity of the obtained weld coating material was 2.139. This weld coating material was welded to the resin base material under the welding conditions shown in Table 1, and the obtained joint structure was evaluated in the same manner as in Example 1.
[0073]
Example 5
The modified PTFE resin powder shown in Table 1 was used as a raw material of the weld coating material. The above-mentioned raw material was filled in a mold and pressurized at 30 MPa, a preform was obtained, and the preform was fired at 370 ° C. for 10 hours, and then skived to obtain a weld coating material. The specific gravity of the obtained weld coating material was 2.137. This weld coating material was welded to the resin base material under the welding conditions shown in Table 1, and the obtained joint structure was evaluated in the same manner as in Example 1.
[0074]
Comparative Example 1
Tetrafluoroethylene homopolymer [TFE homopolymer] powder shown in Table 1 was used as a raw material of the coating material. The above-mentioned raw material was filled in a mold and pressurized at 30 MPa, a preform was obtained, and the preform was baked at 370 ° C. for 10 hours, followed by skiving to obtain a coating material. The specific gravity of the obtained coating material was 2.165. An attempt was made to weld this coating material to the base material under the welding conditions shown in Table 1, but there was no welding reliability and no welding was possible.
[0075]
Comparative Example 2
A TFE / perfluoro (alkyl) vinyl ether copolymer [PFA] powder shown in Table 1 was used as a raw material of the coating material, and the PFA powder was extruded using a screw extruder to obtain a coating material. The specific gravity of the coating material was 2.140. The welding was performed under the welding conditions shown in Table 1 except that the coating material and the base material were welded at 480 ° C., and the same evaluation as in Example 1 was performed on the obtained joined body.
[0076]
Table 1 shows the properties and welding conditions of the (welding) coating material, and Tables 2 to 8 show the evaluation results of the welding state. In Tables 2 to 8, the following resin base materials were used.
Table 2 Sheet obtained from modified polytetrafluoroethylene resin (I)
Table 3: Glass cloth backing sheet obtained from modified polytetrafluoroethylene resin (I)
Table 4: Sheets obtained from TFE homopolymer resin (II)
Table 5: Glass cloth backing sheet obtained from TFE homopolymer resin (II)
Table 6: Sheets obtained from the modified polytetrafluoroethylene resin (III)
Table 7: Glass cloth backing sheet obtained from modified polytetrafluoroethylene resin (III)
[0077]
[Table 1]

[0078]
[Table 2]

[0079]
[Table 3]

[0080]
[Table 4]

[0081]
[Table 5]

[0082]
[Table 6]

[0083]
[Table 7]

[0084]
From the above table, it was found that in any of Examples 1 to 5 using the modified PTFE resin as a raw material of the (welding) coating material, no leaked portion occurred, but PFA was used as a raw material of the (welding) coating material. In Comparative Example 2 used, it was found that a leaked portion 51 as shown in FIG. 5 was generated, and when this was removed, the welded end 52 of the (resin) base material was damaged. Examples 2 to 5 in Table 2 using the modified PTFE resin having a lower melt viscosity than the (resin) base material as the raw material of the (welding) coating material, use the TFE homopolymer as the raw material of the (welding) coating material. It was found that the welding state was better than that of Comparative Example 1 or Comparative Example 2 using PFA as a raw material of the (welding) coating material.
[0085]
Reference Example 1 Exposure test of chemical solution to container using primer
A 3 mm-thick sheet made of polytetrafluoroethylene resin as a base material, PFA used in Comparative Example 2 as a coating material, and a primer (dispersion-stabilized PFA obtained by emulsion polymerization using a surfactant or the like) ) To obtain a joined body under the same conditions as in Comparative Example 2.
The obtained joined body was exposed to sulfuric acid and ozone at a temperature of 120 ° C. for 2 months and observed using a scanning electron microscope [SEM]. As shown in FIG. 4, the boundary between the base material and the coating was observed. It was found that dust was generated.
Based on the obtained SEM image, using a dust counter, the number of dust particles having an average particle diameter of 0.2 μm or more contained per 1 ml of the boundary portion volume between the base material portion and the coating portion was observed. / Ml. When the elongation and tensile strength of the welded portion were measured in the same manner as in Example 1, the tensile strength of the welded portion was reduced by 20% and the elongation was also reduced by 35% as compared to before the above-mentioned exposure. Next, as a result of elemental analysis of the black portion using a mass spectrometer, it was found that the fluorine content was reduced to 50% or less of that of the normal portion which did not change to black.

From the above results, it was presumed that the dust observed by SEM was due to the generation of free floating foreign matter due to the carbonization of the surfactant contained in the primer.
[0086]
【The invention's effect】
Since the welding coating material and the welding method according to the present invention have the above-described configuration, after the welding, the chemical liquid permeation at the joint of the resin base material is small, the welding reliability is excellent, and the welding is performed without any leaked portion. Construction products can be provided.
[Brief description of the drawings]
FIG. 1 is a schematic top view and a schematic cross-sectional view of a sample for measuring welding strength and elongation.
FIG. 2 is a schematic cross-sectional view showing a sampling site of a specific gravity measurement sample.
FIG. 3 is a schematic sectional view showing a welding process.
FIG. 4 is an SEM image of a weld in Reference Example 1.
FIG. 5 is a schematic cross-sectional view of a leak portion and a welded end.
[Explanation of symbols]
11 Weld coating
12 Resin base material
21 Weld coating (for specific gravity measurement)
22 Welding periphery
23 groove recess
31 Weld coating
32 resin base material
33 hot air
34 Pressurization
35 welding run
51 Leakage
52 Weld end

Claims (29)

A weld coating comprising a modified polytetrafluoroethylene resin (A),
The welding covering material is for covering the joining portion of the resin base material by placing and welding on the joining portion of the resin base material made of polytetrafluoroethylene resin (B),
The modified polytetrafluoroethylene resin (A) is a weld coating material comprising tetrafluoroethylene and a trace amount of monomer. The modified polytetrafluoroethylene resin (A) has a trace monomer unit derived from a trace monomer of 0.05 to 0.7% by mass of a copolymer composed of tetrafluoroethylene and the trace monomer. The weld cladding material according to claim 1, which is a certain material. The weld coating material according to claim 1 or 2, wherein the trace monomer is perfluoro (alkyl vinyl) ether and / or hexafluoropropylene. The weld coating material according to claim 1, 2 or 3, having a melt viscosity of 1 × 10 ⁸ to 15 × 10 ⁸ Pa · s. The weld coating according to claim 1, 2, 3, or 4, wherein the resin base material is a lining sheet base material. A joint structure comprising a weld coating material made of a modified polytetrafluoroethylene resin (A) and a joint part of a resin base material made of a polytetrafluoroethylene resin (B),
It is obtained by placing the welding coating material on the joint of the resin base material and performing welding,
A joint structure, wherein the modified polytetrafluoroethylene resin (A) is composed of tetrafluoroethylene and a trace amount of monomer. The modified polytetrafluoroethylene resin (A) has a trace monomer unit derived from a trace monomer of 0.05 to 0.7% by mass of a copolymer composed of tetrafluoroethylene and the trace monomer. 7. The joined structure according to claim 6, wherein the joined structure is provided. The joint structure according to claim 6 or 7, wherein the trace amount monomer is perfluoro (alkyl vinyl) ether and / or hexafluoropropylene. The joint structure according to claim 6, 7 or 8, wherein the weld coating material has a melt viscosity (a) of 1 × 10 ⁸ to 15 × 10 ⁸ Pa · s. The joint structure according to claim 9, wherein the melt viscosity (a) is equal to or less than the melt viscosity (b) of the resin base material. The polytetrafluoroethylene resin (B) is a modified polytetrafluoroethylene resin (B1) composed of tetrafluoroethylene and a trace amount of monomer,
The joint structure does not use a primer between the resin base material and the weld coating material,
The primer is composed of a perfluoro resin (C),
The joint structure according to claim 6, 7, 8, 9 or 10, wherein the perfluoro resin (C) has a melt viscosity of 1 × 10 ⁵ Pa · s or less. The joint structure according to claim 6, 7, 8, 9, 10, or 11, wherein no leakage portion exists. The modified polytetrafluoroethylene resin (A) has a trace monomer unit derived from a trace monomer of 0.05 to 0.5% by mass of a copolymer composed of tetrafluoroethylene and the trace monomer. There is something
The joint structure according to claim 6, 8, 9, 10, 11, or 12, wherein the specific gravity of the weld coating portion derived from the weld coating material is 2.145 to 2.210. The joint structure according to claim 6, 7, 8, 9, 10, 11, 12, or 13, wherein the resin base material is a lining sheet base material. A welding method comprising: placing a welding coating material made of a modified polytetrafluoroethylene resin (A) on a joint of a resin base material made of a polytetrafluoroethylene resin (B);
The modified polytetrafluoroethylene resin (A) comprises a tetrafluoroethylene and a trace amount of a monomer. The modified polytetrafluoroethylene resin (A) has a trace monomer unit derived from a trace monomer of 0.05 to 0.7% by mass of a copolymer composed of tetrafluoroethylene and the trace monomer. The welding method according to claim 15, wherein the welding method is used. 17. The welding method according to claim 15, wherein the trace monomer is perfluoro (alkyl vinyl) ether and / or hexafluoropropylene. The weld coating material has a melt viscosity (a) of 1 × 10 ⁸ to 15 × 10 ⁸ Pa · s,
The welding method according to claim 15, 16, or 17, wherein the melt viscosity (a) is a value equal to or less than the melt viscosity (b) of the resin base material. The joint portion of the resin base material is obtained by filling two resin base materials with a groove and abutting the two resin base materials and filling a recess formed by this with a welding rod.
The welding rod is made of a perfluoro resin (D),
The perfluoro resin (D) has a melt viscosity of 1 × 10 ⁵ Pa · s or less,
The filling of the welding rod is performed by applying a pressure of 0.3 to 2.5 MPa at a welding speed of 70 to 200 mm / min while heating the welding rod to 460 to 550 ° C. 19. The welding method according to 17 or 18. The resin base material is a lining sheet base material,
The welding is performed by applying a pressure of 0.3 to 2.5 MPa at a welding speed of 30 to 140 mm / min while heating so that the contact surface between the joint portion of the resin base material and the welding coating material is at 520 to 620 ° C. The welding method according to claim 15, 16, 17, 18, or 19, which is performed. The resin base material has a specific gravity of 2.175 to 2.200,
The modified polytetrafluoroethylene resin (A) has a trace monomer unit derived from a trace monomer of 0.05 to 0.5% by mass of a copolymer composed of tetrafluoroethylene and the trace monomer. 21. The welding method according to claim 15, 17, 18, 19, or 20. The welding method according to claim 15, 16, 17, 18, 19, 20, or 21, wherein welding does not generate a leaked portion. The polytetrafluoroethylene resin (B) is a modified polytetrafluoroethylene resin (B1) composed of tetrafluoroethylene and a trace amount of monomer,
The welding coating material is to be placed on the joint of the resin base material without using a primer on the resin base material,
The primer is composed of a perfluoro resin (C),
The welding method according to claim 15, 16, 17, 17, 18, 19, 20, 21, or 22, wherein the perfluoro resin (C) has a melt viscosity of 1 × 10 ⁵ Pa · s or less. A joint structure composed of a joint portion of a resin base material and a weld coating material,
A joint structure obtained by the welding method according to claim 15, 16, 17, 18, 19, 20, 21, 22, or 23. A welded article having the joint structure according to claim 6, 7, 8, 9, 10, 11, 12, 13, 14, or 24. The welded product according to claim 25, which is a welding lining material. A composite article comprising a base material and the welded product according to claim 25. The composite article according to claim 27, which is a container, a tank, a tank, a tower, a piping material, a joint, or a stirring blade. 29. The composite article according to claim 28, which is used for a semiconductor manufacturing apparatus.

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