JP2005305949A - Polyamide resin integrally molded product, its manufacturing method and polyamide resin joining auxiliary - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyamide resin integrally molded product having high joining strength and excellent in joining reliability, its manufacturing method and a joining auxiliary capable of mutually joining polyamide resins with high joining strength. <P>SOLUTION: In manufacturing the polyamide resin integrally molded product by applying the joining auxiliary to the joining region of a polyamide resin molded product and welding a separate polyamide resin becoming an addition molded product part to the coated joining region, the joining auxiliary containing dihydroxybenzene and/or dihydroxybenzoic acid as a component (A) and an organic solvent capable of dissolving or dispersing the component (A) as a component (B) is used. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a polyamide resin integrated molded article, a method for producing the same, and a joining aid suitably used for joining polyamide resins.

  Generally, a linear polymer having an amide bond as a repeating unit in the molecule is called a polyamide resin. Among polyamide resins, resins mainly having an aliphatic chain are widely distributed as “nylon” (trade name), and representative examples include nylon 6 and nylon 66.

  Polyamide resin is a crystalline polymer in which hydrogen bonds can be formed between amide bonds of different polymer chains, and its crystal structure is the same as the amide bonds regularly hydrogen bond in the same plane, Each plane is solid and configured in layers.

  Due to the polarity and crystal structure due to the amide bond, the polyamide resin has excellent resistance to hydrocarbon solvents such as gasoline and oil, and has relatively high heat resistance and strength. Therefore, it is widely used as a resin material suitable for automobile parts, machine parts and the like.

  In recent years, these types of automobile parts and the like have become increasingly complex and large in size. For this reason, it has become difficult to obtain a polyamide resin integrated molded product having a desired shape by a single injection molding, extrusion molding or the like. Therefore, an attempt has been made to produce a polyamide resin integrated molded product having a desired shape by dividing and molding into a plurality of polyamide resin molded products and then joining them together.

  For example, in Patent Document 1, a polyamide resin is injection-molded as a secondary molding material for a primary molding made of polyamide resin, and the primary molding and an additional molding portion made of the secondary molding material are welded together. An integrated polyamide resin integral molding is disclosed.

  In addition, for example, there is known a method for manufacturing a polyamide resin integrated molded product in which polyamide resin molded products are welded together and integrated using a welding method such as ultrasonic welding or vibration welding.

  Further, for example, by heating the conductive wire embedded in the primary molded product made of polyamide resin, the polyamide resin as the secondary molding material is injection molded while melting the primary molded product, and the primary molded product and the additional molded product. There is also known a method for producing a polyamide resin integrated molded article using a resistance welding method in which parts are welded to each other.

JP 2000-61983

  However, the conventionally known polyamide resin integrated molded article has a problem that the bonding strength is not sufficient, and therefore, the reliability is insufficient. The cause is presumed to be as follows.

  That is, when a polyamide resin integrated molded product is manufactured using an injection molding method, a primary molded product made of a polyamide resin is set in a mold, and a molten polyamide which becomes an additional molded product portion with respect to the primary molded product A resin is formed by injection molding.

  Usually, there is no amide bond in a free state that does not participate in hydrogen bonding since there is no partner polymer chain to be hydrogen bonded at the bonding site of the primary molded product.

  However, these amide bonds in a free state are bonded to each other by heating the mold during injection molding, and the surfaces of the bonding sites of the primary molded product are associated. Therefore, it is considered that there are very few free amide bonds on the surface of the bonded portion of the primary molded product.

  Therefore, the primary molded product and the additional molded product are crystallized separately without the hydrogen bond between the amide bond on the primary molded product side and the amide bond on the additional molded product side. Therefore, the joint strength of the obtained integrally molded product is very weak.

  In addition to the above, the polyamide resin has an extremely narrow melting point width and a very fast curing time compared to other resins. Therefore, this is also considered to be a cause that the primary molded product and the additional molded product are not sufficiently joined.

  The problem of the decrease in bonding strength as described above may also occur when a polyamide resin integrated molded product is manufactured using a welding method such as ultrasonic welding or vibration welding.

  That is, when producing a polyamide resin integrated molded article using ultrasonic welding or vibration welding, in order to obtain sufficient bonding strength, it is usually bonded while heating and melting not only the surface of the bonding site but also the entire bonding site with vibration energy. There is a need to.

  However, since it is necessary to apply a great deal of vibration energy in order to join the moldings that have been crystallized once, a remelted and resolidified layer that is inferior in strength is generated remarkably at the joining site.

  Therefore, it is difficult to obtain an integrally molded product having sufficient bonding strength by simply using conventional ultrasonic welding or vibration welding. Moreover, in order to ensure sufficient bonding strength, there has been a problem that the thickness of the bonded portion must be designed to be thicker than originally required.

  Further, when the polyamide resin integrated molded product is manufactured using the resistance welding method, it is necessary to embed the conductive wire in the primary molded product, so that the working efficiency is very poor and the manufacturing cost is increased. In addition, on the primary molded product side, a remelted and resolidified layer having inferior strength is generated due to heat generation of the conductive wire, and this may cause a decrease in strength. Further, from the viewpoint of recycling, it is not preferable that the conductive wire is mixed in the integrally molded product.

  The present invention has been made in view of the above problems, and the problem to be solved by the present invention is to provide a polyamide resin integrated molded article having high bonding strength and excellent bonding reliability, and a method for producing the same. There is. Another object of the present invention is to provide a bonding aid capable of bonding polyamide resins with high bonding strength.

  In order to solve the above-mentioned problem, the polyamide resin integrated molded article according to claim 1, wherein a joining assistant is applied to a joint portion of the polyamide resin molded article, and another polyamide resin which becomes an additional molded article portion at the joint portion. Are bonded and integrated, and the bonding aid can dissolve or disperse the component (A) as the component (A), dihydroxybenzene and / or dihydroxybenzoic acid, and the component (B). The main point is to include various organic solvents.

  Further, in the polyamide resin integrated molded product according to claim 2, a bonding assistant is applied to a bonding site of the polyamide resin molded product and / or a bonding site of another polyamide resin molded product. The welding assistant is integrated and is capable of dissolving or dispersing (A) component as dihydroxybenzene and / or dihydroxybenzoic acid, and (B) component as component (A). The gist is to include an organic solvent.

  Moreover, the polyamide resin integrated molded article according to claim 3 is the one according to claim 1 or 2, wherein the content of the component (A) is 10 wt% or more and 50 wt% or less, and the (B) The gist is that the content of the component is 50% by weight or more and 90% by weight or less.

  Further, the polyamide resin integrated molded article according to claim 4 is the one according to claims 1 to 3, wherein the component (B) is a mixed organic solvent in which a plurality of types of the organic solvent are mixed. The gist.

  Moreover, the manufacturing method of the polyamide resin integral molded product according to claim 5 includes a step of applying a bonding aid to a bonding site of the polyamide resin molded product, and another polyamide resin which becomes an additional molded product portion at the bonding site. The bonding aid is composed of dihydroxybenzene and / or dihydroxybenzoic acid as component (A), and an organic solvent capable of dissolving or dispersing component (A) as component (B). Inclusion is included.

  The method for producing a polyamide resin integrated molded product according to claim 6 includes a step of applying a bonding aid to a bonding site of the polyamide resin molded product and / or a bonding site of another polyamide resin molded product, A step of welding the bonding parts to each other, and the bonding aid can dissolve or disperse the component (A) as the component (A), dihydroxybenzene and / or dihydroxybenzoic acid, and the component (B). The main point is to include various organic solvents.

  Moreover, the manufacturing method of the polyamide resin integrated molding of Claim 7 is a thing of Claim 5 or 6, Comprising: Content of the said (A) component is 10 to 50 weight%, The gist is that the content of the component (B) is 50% by weight or more and 90% by weight or less.

  The method for producing a polyamide resin integral molded product according to claim 8 is the method according to claims 5 to 7, wherein the component (B) is a mixed organic solvent in which a plurality of types of the organic solvent are mixed. It is a summary.

  The bonding aid for polyamide resin according to claim 9 is an organic solvent capable of dissolving or dispersing the component (A) as the component (A), dihydroxybenzene and / or dihydroxybenzoic acid as the component (B). It is a summary to include.

  The bonding aid for polyamide resin according to claim 10 is the one according to claim 9, wherein the content of the component (A) is 10% by weight to 50% by weight, and the component (B) The gist of the present invention is that it is 50 wt% or more and 90 wt% or less.

  Further, the polyamide resin joining aid according to claim 11 is the one according to claim 9 or 10, wherein the component (B) is a mixed organic solvent in which a plurality of types of the organic solvents are mixed. This is the gist.

  In the polyamide resin integrated molded article according to claim 1, the surface of the joined portion of the polyamide resin molded product is modified by the joining aid, and another polyamide resin that becomes an additional molded product portion is welded to the joined portion. It is integrated. Therefore, it has high bonding strength and excellent bonding reliability. Further, even if a so-called joining margin or the like is not provided, for example, by increasing the thickness of the joining portion, the joining strength is high.

  Further, in the polyamide resin integrated molded article according to claim 2, the bonding site of the polyamide resin molded product and / or the bonding site of another polyamide resin molded product is surface-modified with the above-mentioned bonding aid, Are welded together and integrated. Therefore, it has high bonding strength and excellent bonding reliability. Further, even if a so-called joining margin or the like is not provided, for example, by increasing the thickness of the joining portion, the joining strength is high.

  In addition, since the polyamide resin integrated molded article according to claim 3 uses the bonding aid having the specific component ratio, the surface of the bonded portion is sufficiently modified.

  Further, the polyamide resin integrated molded article according to claim 4 uses a mixed organic solvent in which a plurality of organic solvents capable of dissolving or dispersing the component (A) are mixed as the component (B) in the bonding aid. ing. Therefore, compared with the case where one kind of organic solvent is used, it is easy to adjust the drying time due to volatilization of the bonding aid, and the coating property of the bonding aid is excellent. Accordingly, the bonding aid is uniformly applied to the bonding portion, and the bonding portion is surface-modified without unevenness, so that the bonding reliability is particularly excellent.

  Moreover, the manufacturing method of the polyamide resin integral molded product according to claim 5 includes a step of applying the joining aid to a joined portion of the polyamide resin molded product, and another polyamide resin that becomes an additional molded product portion at the joined site. And a step of welding. Therefore, a polyamide resin integrated molded article having high bonding strength and excellent bonding reliability can be obtained. In addition, the polyamide resin integrated molded product can be manufactured easily and at a lower cost than the conventional manufacturing method.

  The method for producing a polyamide resin integrated molded article according to claim 6 includes a step of applying the joining aid to a joining part of the polyamide resin molded article and / or a joining part of another polyamide resin molded article, And a step of welding the parts to each other. Therefore, a polyamide resin integrated molded article having high bonding strength and excellent bonding reliability can be obtained. In addition, the polyamide resin integrated molded product can be manufactured easily and at a lower cost than the conventional manufacturing method.

  Moreover, since the manufacturing method of the polyamide resin integrated molded article of Claim 7 uses the joining adjuvant made into the said specific component ratio, a joining site | part is fully surface-modified.

  The method for producing a polyamide resin integrated molded article according to claim 8 is a mixed organic in which a plurality of organic solvents capable of dissolving or dispersing the component (A) are mixed as the component (B) in the bonding aid. A solvent is used. Therefore, compared with the case where one kind of organic solvent is used, it is easy to adjust the drying time due to volatilization of the bonding aid, and the coating property of the bonding aid is excellent. Accordingly, the bonding aid is uniformly applied to the bonding site, and the bonding site is surface-modified without unevenness, so that a polyamide resin integrated molded product particularly excellent in bonding reliability can be obtained.

  Moreover, since the joining aid of the polyamide resin of Claim 9 contains the said (A) component and (B) component, polyamide resin can be joined with high joining strength.

  Moreover, since the joining aid of the polyamide resin according to claim 10 has the specific component ratio, the surface of the joining portion can be sufficiently modified.

  The polyamide resin joining aid according to claim 11 uses, as the component (B), a mixed organic solvent in which a plurality of organic solvents capable of dissolving or dispersing the component (A) are mixed. Therefore, compared with the case where one kind of organic solvent is used, it is easy to adjust the drying time due to volatilization of the bonding aid, and the coating property of the bonding aid is excellent. Therefore, the bonding assistant can be uniformly applied to the bonding portion, and the surface of the bonding portion can be uniformly modified.

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

  The polyamide resin-integrated molded product according to the present invention (hereinafter referred to as “the present polyamide resin-integrated molded product”) is bonded to the bonding part of the polyamide resin molded product (hereinafter referred to as “the present bonding aid”). )) Is applied, and another polyamide resin to be an additional molded part is welded to this joining portion, or the joining portion and / or another polyamide resin molding that the polyamide resin molding has has. The present bonding aid is applied to the bonding sites, and these bonding sites are welded together.

  Specifically, as the former polyamide resin integrated molded product, the present bonding aid is applied to the bonded portion of the polyamide resin molded product, and after this is inserted into a mold, a newly melted polyamide resin is added. Examples thereof include an integrally molded product that can be obtained by welding a polyamide resin molded product and an additional molded product part.

  On the other hand, as the latter polyamide resin integral molded product, specifically, the present bonding aid is applied to the bonding site of the polyamide resin molded product and / or the bonding site of another polyamide resin molded product. Are welded together by various welding methods that involve heat melting of the resin, such as ultrasonic welding, vibration welding, hot plate welding, hot air welding, high frequency welding, spin welding, friction welding, laser welding, electromagnetic induction welding, infrared welding, etc. Examples thereof include an integrally molded product that can be obtained by welding.

  Specific examples of the polyamide resin include aliphatic polyamides such as nylon 6, nylon 66, nylon MX6, nylon 11, nylon 12, nylon 46, nylon 610, and nylon 612, and aromatic polyamides. May be used alone or in combination. Moreover, the polymer alloy type resin containing these polyamide resins may be sufficient.

  The shapes of the polyamide resin integrated molded product and the polyamide resin molded product may be various shapes such as a hollow shape, and can be appropriately selected according to the application.

  The polyamide resin molded product may be obtained by injection molding, blow molding, extrusion molding, transfer molding, compression molding, cutting, or the like. Moreover, the polyamide resin molded product may have a plurality of bonding sites, and is not particularly limited.

  Here, this joining aid used at the time of manufacture of this polyamide resin integrated molding is demonstrated.

  The bonding aid includes dihydroxybenzene and / or dihydroxybenzoic acid as the component (A) and an organic solvent capable of dissolving or dispersing the component (A) as the component (B).

  As the dihydroxybenzene in the component (A), 1,2 dihydroxybenzene (CAS number; RN [120-80-9]) 1,3 dihydroxybenzene (CAS number; RN [108-46-3]), 1, 4-dihydroxybenzene (CAS number; RN [123-31-9]).

  In addition, as the dihydroxybenzoic acid in the component (A), 2,3 dihydroxybenzoic acid (CAS number; RN [303-38-8]), 2,4 dihydroxybenzoic acid (CAS number; RN [89-86- 1]), 2,5 dihydroxybenzoic acid (CAS number; RN [490-79-9]), 2,6 dihydroxybenzoic acid (CAS number; RN [303-07-1]) 3,4 dihydroxybenzoic acid ( CAS number; RN [99-50-3]) and 3,5 dihydroxybenzoic acid (CAS number; RN [99-10-5]).

  The component (A) preferably contains both dihydroxybenzene and dihydroxybenzoic acid. After applying a bonding aid to the surface of the bonding site, it is possible to suppress the oxidation of dihydroxybenzene, and even if the time from application to bonding is increased, the bonding strength is hardly impaired and the productivity is improved. Because it does.

  On the other hand, the organic solvent may be either volatile or non-volatile, but preferably volatile. Moreover, the organic solvent which can melt | dissolve a polyamide resin very slightly can be used suitably.

  Specific examples of the organic solvent include alcohols having 1 to 6 carbon atoms, ketones or aldehydes having 1 to 6 carbon atoms, nitriles having 1 to 6 carbon atoms, and more specifically, Examples thereof include methanol, ethanol, isopropyl alcohol, acetone, acetonitrile and the like, and these may be used alone or in combination.

  At this time, when mixing multiple organic solvents and using them as mixed organic solvents, consider the temperature environment and working environment in which this bonding aid is used, and the bonding aid will be immediately after application to the bonding site. There is an advantage that the drying time can be appropriately adjusted so as not to be dried.

  Here, the blending ratio of the component (A) and the component (B) is such that the content of the component (A) is 10% by weight or more and 50% by weight or less from the viewpoint that the bonding site can be sufficiently surface-modified. The content of the component (B) is preferably in the range of 50% by weight to 90% by weight.

  Preferably, the content of the component (A) is 10% by weight or more and 35% by weight or less, the content of the component (B) is 65% by weight or more and 90% by weight or less, and more preferably, the content of the component (A) It is preferable that the content is in the range of 10 wt% to 25 wt%, and the content of the component (B) is in the range of 75 wt% to 90 wt%.

  At this time, if the content of the component (A) exceeds 50% by weight and the content of the component (B) is less than 50% by weight, it is difficult to dissolve or disperse the component (A) in the component (B). Since the tendency to become is seen, it is not preferable.

  The present bonding aid may be produced by any production method as long as it can uniformly dissolve or disperse the component (A) in the component (B), and is not particularly limited. It is not something.

  In addition, the above-mentioned polyamide resin, dye, thickener, antioxidant and the like may be added to the present bonding aid as long as the surface modification action on the polyamide resin is not impaired.

  For example, when a polyamide resin is added, bonding reliability can be improved. This is presumed to be because the unevenness on the surface of the joining site is reduced and the contact area is increased by the added polyamide resin.

  At this time, it is preferable to use the same type of polyamide resin as the molded product to be joined as the polyamide resin to be added.

  Further, for example, when a dye is added, the state of application to the bonding site can be visually confirmed. For this reason, the coating workability is improved, and coating unevenness can be reduced.

  In addition, for example, when a thickener is added, effects such as sagging and uniform application can be obtained when the bonding aid is applied.

  The method for applying the bonding aid to the bonding site is not particularly limited as long as it can be thinly applied to the bonding site and applied quantitatively. Specifically, various application methods such as application with a brush and application with a sponge can be used.

  Here, the reason why the present polyamide resin integrated molded article has high bonding strength is presumed as follows.

  That is, when the present bonding aid is applied to the bonding site of the polyamide resin molded product, the polyamide resin on the surface of the bonding site is activated by the reducing action of the component (A). Then, when molten polyamide resin is applied to the activated bonding sites or the bonding sites are welded to each other, in the process of recrystallization of the molten polyamide resin, both are strongly strengthened mainly by chemical bonds. Connected and integrated.

  Therefore, it is presumed that the obtained polyamide resin integrated molded article has a high bonding strength comparable to that of the molded article integrally molded at one time.

  Hereinafter, the present invention will be described more specifically with reference to examples.

1. Example using injection welding method (production of bonding aid according to this example)
First, a bonding aid according to the present example was prepared by the following procedure. That is, as shown in Tables 1 to 7 described later, 1,3 dihydroxybenzene, 3,5 dihydroxybenzoic acid as the component (A), methanol, isopropyl alcohol, acetonitrile, acetone as the component (B) have a predetermined weight. It mix | blended so that it might become ratio, and it mixed well using the stirrer, and obtained the joining adjuvant which concerns on a present Example.

  At this time, nylon 6 resin was added for some joining aids. Nylon 6 resin was added by adding finely pulverized nylon 6 resin to the solution and mixing with heating using a stirrer.

  1,3 dihydroxybenzene, 3,5 dihydroxybenzoic acid, methanol, isopropyl alcohol, acetonitrile, and acetone are all manufactured by Wako Pure Chemical Industries, Ltd., and nylon 6 resin is “Ube Nylon 1013” manufactured by Ube Industries, Ltd. It is.

(Preparation of test piece T ₁ according to the present embodiment)
Figure 1 is an external perspective view of a primary molded portion T ₁₁ constituting the test piece T ₁ and the same. Figure 2 is an external perspective view of a mold used in molding a test piece T ₁ by injection molding.

Then, by the following procedure, and the test piece T ₁ made of a polyamide resin produced by injection molding. That is, in advance in the joint end face 1 of the primary molding section T ₁₁ was molded by injection molding was uniformly applied to the bonding aid in brush according to the present embodiment, it is set into the mold 2, 3, additional molding section the T ₁₂ were injection added. Thus, the additional molding section T ₁₂ and the primary molding section T ₁₁ is molded to produce a test piece T ₁ according to the present embodiment which is integrated is welded.

Here, the test strip T ₁ is formed into a dumbbell shape, and has a uniform thickness. An additional molding section _{T 12} and the primary molding section _{T 11} is the same shape (the length _{L 1} × width _{W 1} × thickness _{K 1 = 75 × 10 × 3mm} ), a test piece _{T 1} which both are joined The total length is 150 mm.

Further, the material of the test piece _{T 1,} nylon 6 resin (manufactured by Mitsubishi Engineering-Plastics Corporation, "Novamid 1013CH5") or nylon 66 resin (Mitsubishi Engineering Plastics Corporation, "Novamid 3010SR") was used.

  The conditions for injection molding were as follows. That is, “NN-50 Hypershot 3000” manufactured by Niigata Steel was used as the injection molding apparatus, and the molding temperature of nylon 6 was 231-230-225-225 ° C. in order from the injection nozzle. On the other hand, about nylon 66, it was set as 280-275-275-270 degreeC in order from the injection nozzle. In both cases, the mold temperature was set to 85 ° C.

(Evaluation of the test piece T ₁ according to the present embodiment)
Evaluation of the test strip T ₁ was performed as follows. That is, the test piece T ₁ is subjected to a tensile test in a constant temperature room at 23 ° C. and 50% humidity (number of samples: N = 5), and the maximum tensile strength until the test piece T ₁ is broken is measured. did. At this time, the test speed was 50 mm / min. A universal material testing machine (INSTRON 4505) was used as the tensile testing apparatus.

(Bonding auxiliaries and test piece T ₁ of the test results according to the present embodiment)
The test results of the joining auxiliaries and test piece T ₁ according to this embodiment is shown in Table 1 to Table 7.

  The test pieces according to Examples 1 to 30 are made of nylon 6 resin, and the test pieces according to Examples 32 to 34 are made of nylon 66 resin.

(Test results of bonding aid and test piece according to comparative example)
First, the test piece which concerns on Comparative Examples 1-5 is demonstrated.
(Comparative Example 1)
A test piece according to Comparative Example 1 was produced in the same manner as the test piece T _{1 according} to the example except that nylon 6 resin was used and the whole was molded into the same shape as the test piece T ₁ by one injection molding.
The test piece according to Comparative Example 1 had a tensile strength of 75.1 MPa and a standard deviation of 0.3 MPa.

(Comparative Example 2)
Except for not any applied a bonding aid joining end surface 1 of the primary molded portion T ₁₁ in the same manner as the test piece T ₁ according to the embodiment, to produce a test piece according to Comparative Example 2. In addition, nylon 6 resin was used for the material of the test piece.
The test piece according to Comparative Example 2 had a tensile strength of 17.3 MPa and a standard deviation of 0.2 MPa.

(Comparative Example 4)
A test piece according to Comparative Example 4 was prepared in the same manner as the test piece T _{1 according} to the example except that the nylon 66 resin was used and the whole was molded into the same shape as the test piece T ₁ by injection molding.
The test piece according to Comparative Example 4 had a tensile strength of 78.7 MPa and a standard deviation of 1.6 MPa.

(Comparative Example 5)
Except for not any applied a bonding aid joining end surface 1 of the primary molded portion T ₁₁ in the same manner as the test piece T ₁ according to the embodiment, to produce a test piece according to Comparative Example 5. Nylon 66 resin was used as a material for the test piece.
The test piece according to Comparative Example 5 had a tensile strength of 6.86 MPa and a standard deviation of 1.6 MPa.

(Consideration of the above test results)
It can be seen that the test pieces according to Examples 1 to 30 (use of nylon 6) have inferior bonding strength as compared with the test piece according to Comparative Example 1 manufactured by one injection molding.

  Similarly, the test pieces (using nylon 66) according to Examples 32 to 34 have a bonding strength comparable to that of the test piece according to Comparative Example 4 manufactured by one injection molding. I understand.

  Moreover, it turns out that the test piece which concerns on Examples 1-30 has the very outstanding joining strength compared with the test piece which concerns on the comparative example 2 joined without using a joining adjuvant.

  Similarly, it turns out that the test piece which concerns on Examples 32-34 has the joint strength which was very excellent compared with the test piece which concerns on the comparative example 5 joined without using a joining adjuvant.

This is because, when the bonding aid according to the present embodiment is applied to the surface of the bonding end surface 1, the polyamide resin on the surface of the bonding end surface 1 is activated by the reducing action of the component (A), and this activated bonding end surface by applying the molded portion T ₁₂ is injected welded to 1, the polyamide resin in a molten state in the course of recrystallization, both are presumed to be due to integrated tied firmly mainly by chemical bonding.

(Relationship between drying time of bonding aid and tensile strength)
Next, after applying the bonding aid according to Example 1 and Example 26 to the surface of the bonding end face 1, the test piece T ₁ is molded every time a certain period of time has elapsed. It was investigated the relationship between the tensile strength of the test piece T _1. The result is shown in FIG.

  According to FIG. 3, the test piece according to Example 1 and the test piece according to Example 26 have the same bonding strength in the initial stage of drying, but the test piece according to Example 1 increases as the drying time increases. There was a tendency for the bonding strength to gradually decrease.

  On the other hand, in the test piece according to Example 26, almost no decrease in bonding strength was observed within the measured drying time range.

  This is because the test piece according to Example 26 contains both 1,3 dihydroxybenzene and 3,5 dihydroxybenzoic acid as the component (A) in the bonding aid, and thus oxidation of 1,3 dihydroxybenzene. It is presumed that the surface modification action by component (A) was maintained for a long time.

(AFM measurement of joint end face)
Next, a state in which the joining end face 1 is slightly dissolved will be described with respect to a result of measurement with a 5 μm scale AFM.

  FIG. 4 is an AFM result of the surface of the joining end face 1 before applying the joining aid. FIG. 5 is an AFM result of the surface of the joining end face 1 to which only methanol is applied.

  Noise appearing in a triangular shape at the upper left end of FIG. 4 (a convex portion that is too large to be measured in the AFM measurement on the 5 μm scale) disappears in FIG. It can be seen that nylon 6 has dissolved.

  Next, a state in which the bonding end face 1 is surface-modified will be described with respect to a result of measurement by the AFM.

  6 to 8 are AFM results of the surface of the joining end face 1 to which the joining aid according to Example 23 was applied. 6 shows the results after 5 minutes of application, FIG. 7 shows the results after 24 hours of application, and FIG. 8 shows the results after 96 hours of application.

  As shown in FIG. 6, it can be seen that the surface of the joining end face 1 after 5 minutes of application is free from the noise shown in FIG. 4 and is deformed into a gentle uneven surface.

  In addition, it can be seen that as the time of application 24 hours and 96 hours elapses, dissolution of the surface of the joining end face 1 proceeds, and the uneven surface is further flattened.

  From this, it can be seen that the bonding aid according to Example 23 continues to act on the bonded end surface 1 in a dry state for a long time, and melts and deforms the bonded end surface 1.

  That is, 1,3 dihydroxybenzene and 3,5 dihydroxybenzoic acid are dissolved in the bonding aid according to Example 23 in addition to the organic solvent of methanol and isopropyl alcohol.

  When a bonding aid is applied to the bonding end face 1, methanol and isopropyl alcohol volatilize soon after the application.

  However, 1,3 dihydroxybenzene and 3,5 dihydroxybenzoic acid remain on the joint end face 1 even after application and continue to act on the joint end face 1 for a long time. Therefore, the amorphous state of the polyamide resin on the surface of the joining end face 1 is maintained for a long time.

  Accordingly, when both 1,3 dihydroxybenzene and 3,5 dihydroxybenzoic acid are included, the bonding strength after bonding is not impaired even if the bonding treatment is not performed immediately after the application of the bonding aid, and various bondings are possible. It can be said that it can correspond to a work process.

(Confirmation of crystallinity of polyamide resin)
In general, in the infrared absorption spectrum of a polymer, the crystallinity can be estimated by finding an absorption position peculiar to a crystalline region and an absorption position peculiar to an amorphous region. Therefore, the crystallinity of the polyamide resin on the joint end face 1 and the association state of the amide bond were confirmed by an infrared absorption spectrum.

Crystalline absorption of nylon 6 is 1030,936Cm ^-1, absorption of amorphous corresponding thereto are respectively 990,1139cm ^-1.

In joining end surface 1 of Example 23 in the primary molding section T ₁₁ of the joining auxiliary agent was applied according a result of analyzing with plot out only spectrum of increase or decrease in the coating back and forth over a period of about 3 days, in the vicinity of 1000 cm ^-1 It was confirmed that the absorption line showing crystallinity decreased, and that the absorption line showing amorphous was increased instead. Further, it was confirmed that in the vicinity of 936 cm ⁻¹ , the absorption line indicating crystallinity decreased, and the absorption line of 1139 cm ⁻¹ indicating amorphous was increased instead.

Further, characteristic absorption by amide bond, has absorbed due to absorption and N-H amide I by its carbonyl group, the absorption showing the respective association ^state, 1650 cm -1, a 3360Cm ^-1, corresponding to their absorbing showing a non-association state and ^has, 1690 cm -1, is 3420cm ^-1.

Was analyzed by the same manner as described above infrared absorption spectrum, the absorption of reduced 1650 cm ^-1, a pair of absorption of 1690 cm ^-1 in the non-associated increasing instead is confirmed, when the same pair also the N-H Absorption was confirmed.

2. Example Using Ultrasonic Welding Method Next, when joining the polyamide resin moldings by ultrasonic welding, the case where the joining aid according to the present invention is applied to the joining site and the case where it is not applied are integrally molded. The bonding strength of the objects was compared. This will be described below.

(Preparation and evaluation method of the test piece T ₂ according to the present embodiment)
Figure 9 is an external perspective view of a first mold portion _{T 21} and the second mold portion _{T 22.} Figure 10 is a first mold portion _{T 21} and the second mold portion _{T 22} is a cross-sectional view at the time of ultrasonic welding. Figure 11 is a perspective view showing a state of performing a shear test specimens T _2. 12 is a cross-sectional view taken along line XX of FIG.

As shown in FIG. 9, the test piece T < _b > ₂ includes a first molding part T _< b> ₂₁ and a second molding part T <b> ₂₂ . The second molding portion T _22, the protruding portion 5 of the rectangular frame shape is formed integrally with the substrate portion 4 of rectangular shape, the surface of the projecting portion 5 is of substantially plate-shaped became joining end face 6. On the other hand, the first molding part T ₂₁ has the same shape as the substrate part 4 of the second molding part T ₂₂ , and has a plate-like shape whose surface becomes the joining end surface 7.

The shape of the substrate part 4 and the first molding part T ₂₁ of the second molding part T ₂₂ is L ₂ × width W ₂ × thickness K ₂ = 25 × 17 × 3 mm. The external dimensions (L ₂ × W ₃ ) and internal dimensions (L ₃ × W ₄ ) of the protrusions 5 of the second molding part T ₂₂ are 25 × 12.6 mm and 20.4 × 8 mm, respectively. the thickness _{K 3} of 5 is 1 mm. The first mold portion T _21, the joint end surfaces 7 and 6 of the second molding portion T ₂₂ is a state of being molded, such as surface roughening is not performed.

Further, the entire surface of the joining end face 6 of the second mold section T _22, after applying the joining auxiliary agent according to the present embodiment, the joint end face 7 of the joining end face 6 and the first mold portion T ₂₁ of the second mold portion T ₂₂ in close contact and in which, the addition of vibrations by applying a vibrator 8 of the ultrasonic vibration device on the upper surface of the first mold portion T _21, both by ultrasonic welding, to obtain a molded product serving test piece T ₂ . The ultrasonic vibration device used was “BRANSON 8300”, and the welding time and welding force were 0.4 seconds and 392 N, respectively.

Further, as shown in FIGS. 11 and 12, on the outer side of the first mold portion T ₂₁ joined as described above and the second mold section T _22, that each covering covers the pulling jig 9,10 separate Thus, the first molding part T ₂₁ and the second molding part T ₂₂ were accommodated in the recesses 9a and 10a, respectively.

  Next, the pulling jigs 9 and 10 were fastened so as not to be separated in a state where only the sliding in the pulling direction was allowed. On the opposing surfaces of the pulling jigs 9 and 10, grip pieces 9b and 10b gripped by the grip portion of the tensile test apparatus are respectively provided so as to protrude.

Thus, each gripping pieces 9b of each tension member 9,10, gripped by the gripping portions of 10b a tensile tester, the addition of tensile force to the other by fixing the the other hand, the first forming the test piece T ₂ a Department _{T 21} is the bonding interface of the second mold portion _{T 22} shearing force acts. By measuring the shear force was measured the bonding strength of the test piece T ₂ (the number of samples N = 5).

As the material of the test piece T _2, using the above-mentioned nylon 6 resin, nylon 66 resin. In addition, as a joining aid, a joining aid according to Example 23 described above was used, and no joining aid was used as a comparative example. At this time, the comparative example was set to 0.8 seconds because the bonding was insufficient when the welding time was 0.4 seconds.

(Evaluation Results of the test piece T ₂ according to the present embodiment)
The evaluation results of the test piece T ₂ according to the present embodiment, shown in Table 8 together with comparative examples.

The test piece (using nylon 6) according to the comparative example joined without using the joining aid according to this example had an average shearing force of 3.4 MPa. On the other hand, the test piece T ₂ (using nylon 6) using the joining aid according to the present example has an average shear force of 17.8 MPa, which is more than five times the shear of the test piece according to the comparative example. It was confirmed that it has power.

Similarly, the test piece (using nylon 66) according to the comparative example joined without using the joining aid according to this example had an average shearing force of 1.5 MPa. On the other hand, the test piece T ₂ (using nylon 66) using the joining aid according to this example has an average shearing force of 18.1 MPa, which is more than 12 times the shear strength of the test piece according to the comparative example. It was confirmed that it has power.

However, results of this study, in any of the test, shear (fracture) site of the test piece T ₂ according to the embodiment, rather than the joint interface, the first shaping section T _21, any of the second molding portion T ₂₂ It was.

  Thus, even when the ultrasonic welding method is used as the welding method, it is confirmed that a polyamide resin integrated molded article having a high bonding strength can be obtained as in the case of using the above-described injection welding method. did it.

  The present invention is not limited to the above embodiments, and various modifications can be made without departing from the spirit of the present invention. For example, in the above-described embodiment, the case where the polyamide resin integral molded product is produced using the injection welding method and the ultrasonic welding method has been described. It is also possible to produce a polyamide resin integrated molded article by welding to each other using the joining aid according to the invention.

It is an external perspective view of a primary molded portion T ₁₁ constituting the test piece T ₁ and the same according to the present embodiment. The test piece T ₁ according to the present embodiment is an external perspective view of a mold used in molding by injection molding. For the test piece T ₁ according to Example 1 and Example 26 is a diagram showing the relationship between the drying time and the tensile strength. It is the result of having observed the surface of the joining end surface 1 before apply | coating a joining auxiliary agent with AFM. It is the result of having observed the surface of the joining end surface 1 which apply | coated only methanol with AFM. It is the result of apply | coating the joining adjuvant which concerns on Example 23, and AFM-observing the surface of the joining end surface 1 5 minutes after. It is the result of having applied the joining adjuvant which concerns on Example 23, and observed the surface of the joining end surface 1 24 hours after AFM observation. It is the result of apply | coating the joining adjuvant which concerns on Example 23, and AFM-observing the surface of the joining end surface 1 after 96 hours. It is an external perspective view of a first mold portion _{T 21} and the second mold portion _{T 22.} The first forming portion T ₂₁ and the second mold portion T ₂₂ is a cross-sectional view at the time of ultrasonic welding. Is a perspective view showing a state of performing a shear test specimens T _2. It is the XX sectional view taken on the line of FIG.

Explanation of symbols

T ₁ test piece T ₁₁ primary molding part T ₁₂ additional molding part 1 joint end face T ₂ test piece T ₂₁ first molding part T ₂₂ second molding part 6 joint end face 7 joint end face

Claims (11)

A polyamide resin integrated molded product obtained by applying a bonding assistant to a bonding site of the polyamide resin molded product and welding and integrating another polyamide resin to be an additional molded product part to the bonded site,
The joining aid contains dihydroxybenzene and / or dihydroxybenzoic acid as the component (A), and an organic solvent capable of dissolving or dispersing the component (A) as the component (B). Moldings. A polyamide resin integrated molded article in which a bonding assistant is applied to a bonding site of a polyamide resin molded product and / or a bonding site of another polyamide resin molded product, and these bonding sites are welded together to be integrated. ,
The joining aid contains dihydroxybenzene and / or dihydroxybenzoic acid as the component (A), and an organic solvent capable of dissolving or dispersing the component (A) as the component (B). Moldings.   The content of the component (A) is 10% by weight or more and 50% by weight or less, and the content of the component (B) is 50% by weight or more and 90% by weight or less. Polyamide resin integrated molding.   4. The polyamide resin integrated molded article according to claim 1, wherein the component (B) is a mixed organic solvent in which a plurality of types of the organic solvent are mixed. Applying a bonding aid to the bonding site of the polyamide resin molding,
A step of welding another polyamide resin to be an additional molded part to the joining portion,
The joining aid contains dihydroxybenzene and / or dihydroxybenzoic acid as the component (A), and an organic solvent capable of dissolving or dispersing the component (A) as the component (B). Manufacturing method of a molded product. A step of applying a bonding aid to the bonding site of the polyamide resin molding and / or the bonding site of another polyamide resin molding;
A step of welding these joining sites to each other,
The joining aid contains dihydroxybenzene and / or dihydroxybenzoic acid as the component (A), and an organic solvent capable of dissolving or dispersing the component (A) as the component (B). Manufacturing method of a molded product.   The content of the component (A) is 10 wt% or more and 50 wt% or less, and the content of the component (B) is 50 wt% or more and 90 wt% or less. A method for producing a polyamide resin integrated molded product.   The method for producing an integrally molded polyamide resin product according to claim 5, wherein the component (B) is a mixed organic solvent in which a plurality of types of the organic solvent are mixed.   (A) Component (A) includes dihydroxybenzene and / or dihydroxybenzoic acid, and component (B) includes an organic solvent that can dissolve or disperse component (A).   10. The polyamide resin according to claim 9, wherein the content of the component (A) is 10% by weight to 50% by weight and the content of the component (B) is 50% by weight to 90% by weight. Joining aids.   11. The polyamide resin bonding aid according to claim 9, wherein the component (B) is a mixed organic solvent in which a plurality of types of the organic solvent are mixed.