JP4451201B2 - Manufacturing method of polyamide resin integrated molded article and polyamide resin integrated molded article manufactured by the manufacturing method - Google Patents

Description

  The present invention relates to a method for producing a polyamide resin integrated molded article and a polyamide resin integral molded article produced by the production method.

  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 and the like, by joining the bonded portions of a plurality of polyamide resin molded articles by bringing a heated hot plate close to each other, the molten portion is crimped and welded (so-called hot plate) Welding method), and a production method for producing a polyamide resin integral molded product is disclosed.

JP 2003-13037 A

  However, when the polyamide resin integrated molded product is manufactured using the hot plate welding method or the like, there are the following problems.

  That is, the polyamide resin has characteristics such as an extremely narrow melting point width and a very fast curing time compared to other resins. Therefore, for example, in order to join the polyamide resin molded products using the hot plate welding method, it is necessary to heat and melt the surface of the bonded portion of the polyamide resin molded product over an excessive amount of time and heat.

  Therefore, there is a problem that the joining process takes time and productivity is deteriorated. Further, there has been a problem that the polyamide resin is easily carbonized by exposing the surface of the bonding site to high heat for a long time. In addition, due to excessive heat, a remelted and resolidified layer having poor strength is likely to be generated, and it is difficult to obtain high bonding strength.

  In addition, it is necessary to form a so-called joining margin by increasing the thickness of the joining portion, thereby ensuring the joining strength, and thus there is a problem that the degree of freedom of shape of the polyamide resin integrated molded product is low. It was.

  Furthermore, since the melted polyamide resin protrudes from the bonding interface when the bonding sites are pressure-bonded to each other, it is necessary to provide ribs around the bonding sites so that they are not exposed from the outer surface of the product. There was a problem of poor appearance quality.

  The present invention has been made in view of the above problems, and the problem to be solved by the present invention is a polyamide resin having high bonding strength and excellent bonding reliability even when the bonding time is shorter than the conventional one. An object of the present invention is to provide a production method capable of obtaining an integrally molded product. In addition, another problem to be solved by the present invention is to provide a production method for obtaining a polyamide resin integrated molded article having high bonding strength and excellent appearance quality without providing a bonding margin or the like at the bonding site. There is to do.

In order to solve the above-mentioned problems, the method for producing a polyamide resin integrated molded product according to the present invention includes a step of applying a bonding aid to a bonding site of a polyamide resin molded product and / or a bonding site of another polyamide resin molded product. And a step of heating and melting the polyamide resin on the surface of the joining portion, a step of crimping and joining the joining portions to each other, and a step of cooling the fused and integrated polyamide resin integrated molded product. The bonding aid includes, as component (A), 1,2 dihydroxybenzene, 1,3 dihydroxybenzene, 1,4 dihydroxybenzene, 2,3 dihydroxybenzoic acid, 2,4 dihydroxybenzoic acid, 2,5 dihydroxy. Benzoic acid, 2,6 dihydroxybenzoic acid, 3,4 dihydroxybenzoic acid, 3,5 dihydroxybenzoic acid, 1,2,3 Rehydroxybenzene, 1,2,4 trihydroxybenzene, 1,3,4 trihydroxybenzene, 2,3,4 trihydroxybenzoic acid, 2,4,6 trihydroxybenzoic acid, 3,4,5 trihydroxybenzoic acid Acid and at least one compound selected from these hydrates (provided that 1,3 dihydroxybenzene, 3,5 dihydroxybenzoic acid, and at least one compound selected from these hydrates) And (B) as a component, an organic solvent capable of dissolving or dispersing the component (A) is included.

In the method of manufacturing the polyamide resin integrally molded product of the previous SL amount of the component (A) is 1% by weight to 50% by weight, the component (B) content is more than 50 wt% 99 wt% or less Preferably there is .

In the method of manufacturing the polyamide resin integrally molded product of the previous SL (B) component, it is preferable that the organic solvent is a mixed organic solvent in which a plurality kinds mixed.

In the method of manufacturing the polyamide resin integrally molded product is heated and melted prior Symbol polyamide resin is due to be close to or contact the plate-like member heated to meltable temperature the polyamide resin in the bonding portion surface Is preferred .

Further, the polyamide resin integrally molded product is summarized in that those produced by the production method of the polyamide resin integrally molded product.

  The polyamide resin integral molded article obtained by the method for producing a polyamide resin integral molded article according to the present invention has a surface modification of the joining part of the polyamide resin molded article and / or the joining part of another polyamide resin molded article by the joining aid. These joining parts are welded together and integrated.

  Therefore, according to the manufacturing method of the polyamide resin integrated molded product according to the present invention, it is possible to manufacture a polyamide resin integrated molded product having high bonding strength and excellent bonding reliability.

  Moreover, since it is not necessary to heat and melt the bonding part surface excessively in order to obtain a high bonding strength, the bonding can be performed in a shorter bonding time than before, and the productivity is improved. Further, carbonization of the remelted and resolidified layer or polyamide resin which is inferior in strength hardly occurs.

  In addition, since the bonding sites are bonded mainly by chemical bonding, the polyamide resin molded products are firmly bonded to each other even when the bonding area is small. Therefore, even when the bonding area is only about the wall thickness of the polyamide resin molded product, a polyamide resin integrated molded product having high bonding strength can be produced. In addition, since there is no need to form a joining margin by increasing the thickness of the joining portion, thereby ensuring the joining strength, it is possible to produce a polyamide resin integrated molded article having excellent shape flexibility.

  In addition, since the protruding part that occurs when crimping the joint parts can be suppressed as much as possible, it is not necessary to provide ribs around the joint parts so that they are not exposed from the outer surface of the product, and polyamide resin integrated molding with excellent appearance quality Can manufacture things.

  At this time, when the content of the component (A) in the bonding aid is in the range of 1 wt% to 50 wt% and the content of the component (B) is in the range of 50 wt% to 99 wt%. The above-mentioned effects are excellent.

  When a mixed organic solvent in which a plurality of organic solvents capable of dissolving or dispersing the component (A) is used as the component (B) in the bonding aid, a single organic solvent is used. In comparison, it is easy to adjust the drying time due to volatilization of the bonding aid, etc., 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.

  Further, if the polyamide resin is heated and melted by a method in which a plate-like member heated to a temperature at which the polyamide resin can be melted is brought close to or in contact with the surface of the joining site, the polyamide resin on the surface of the joining site can be relatively easily obtained. Can be melted by heating.

  On the other hand, since the polyamide resin integral molded product according to the present invention is manufactured by the above-described manufacturing method, it has high bonding strength and excellent bonding reliability. In addition, the carbonization of the polyamide resin on the surface of the joining site hardly occurs. Moreover, it is excellent in shape freedom and appearance quality.

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

  The method for producing a polyamide resin integrated molded product according to the present invention (hereinafter referred to as “the present production method”) includes a joining aid at a joining site of a polyamide resin molded product and / or a joining site of another polyamide resin molded product. A step of heating and melting the polyamide resin on the surface of the joining portion, a step of crimping and joining the joining portions to each other, and a step of cooling the fused and integrated polyamide resin integrated molded product. Have.

  In this production method, the polyamide resin molded product refers to a product obtained by dividing a polyamide resin integrated molded product to be finally produced into a plurality of parts. Specifically, this polyamide resin molded product can be manufactured using injection molding, blow molding, extrusion molding, transfer molding, compression molding, cutting, or the like.

  Here, the polyamide resin molded product may have a plurality of bonding sites, and is not particularly limited. Moreover, as long as the polyamide resin molding has a joint part, another polyamide resin molding may already be joined to another joint part. Moreover, the shape of the polyamide resin molded product can be appropriately selected according to the application, such as a hollow shape.

  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. These may be used alone or in combination of two or more. Moreover, the polymer alloy type resin containing these polyamide resins may be sufficient.

  In this production method, the means 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 quantitatively applied. Specifically, various application means such as application with a brush or application with a sponge can be used.

  In the present production method, as a means for heating and melting the polyamide resin on the surface of the bonding site, various heating and melting means such as a hot plate, ultrasonic wave, vibration, hot air, high frequency, laser, electromagnetic induction, and infrared can be used, These may be used alone or in combination.

  Among these, a hot plate heated to a temperature at which the polyamide resin can be melted can be suitably used from the viewpoint that the polyamide resin on the surface of the joining portion can be heated and melted easily and reliably.

  The polyamide resin may be heated and melted in a state where the heating and melting means is in direct contact with the surface of the joining site or in a non-contact state.

  At this time, the time for heating and melting can be appropriately determined in consideration of the type of heating and melting means, the area of the joining portion, and the like.

  Note that if the heating and melting time is too short, bonding can be performed, but sufficient bonding strength tends to be not obtained. On the other hand, if the heating and melting time becomes too long, not only the joining process takes time, but also the surface of the joining site progresses, which may adversely affect the strength of the joining surface. In addition, the melted resin is likely to protrude from the bonding interface, and problems such as poor appearance quality are likely to occur.

  In this manufacturing method, the means for press-bonding the bonded parts to each other is predetermined in the direction in which the bonded parts approach each other with the bonded part of the polyamide resin molded product facing the bonded part of another polyamide resin molded product. Any pressing means can be used as long as it can pressurize at a predetermined pressure for a time.

  In this production method, as a means for cooling the fused and integrated polyamide resin molded product, various cooling means such as air cooling, water cooling, and cooling can be used, and these can be used alone or in combination. May be used.

  Here, in the present manufacturing method, a novel joining aid that has not been conventionally used is applied to the joining portion. Hereinafter, this joining aid will be described in detail.

  The above-mentioned joining aid is, as (A) component, dissolved at least one compound selected from dihydroxybenzene, dihydroxybenzoic acid, trihydroxybenzene and trihydroxybenzoic acid, and (B) component dissolves (A) component or Contains a dispersible organic solvent.

  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]).

  Examples of dihydroxybenzoic acid include 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]), 3,5 dihydroxybenzoic acid (CAS number; RN [99-10-5]).

  Examples of trihydroxybenzene include 1,2,3 trihydroxybenzene (CAS number; RN [87-66-1], pyrogallol), 1,2,4 trihydroxybenzene (CAS number; RN [533-73- 3]), 1,3,5 trihydroxybenzene (CAS number; RN [108-73-6]), 1,3,5 trihydroxybenzene dihydrate (CAS number; RN [6099-90-7]) ).

  Examples of trihydroxybenzoic acid include 2,3,4 trihydroxybenzoic acid (CAS number; RN [610-02-6]) and 2,4,6 trihydroxybenzoic acid (CAS number; RN [83-30). -79]), 2,4,6 trihydroxybenzoic acid monohydrate (CAS number; RN [71989-93-0]), 3,4,5 trihydroxybenzoic acid (CAS number; RN [149-91) -7], gallic acid), 3,4,5 trihydroxybenzoic acid monohydrate (CAS number; RN [5995-86-8]).

  These compounds may be used alone or in combination. Specific examples include dihydroxybenzene and dihydroxybenzoic acid, trihydroxybenzene and trihydroxybenzoic acid, trihydroxybenzene and / or trihydroxybenzoic acid and dihydroxybenzene and / or dihydroxybenzoic acid.

  On the other hand, the organic solvent of component (B) may be either volatile or non-volatile, but preferably a volatile one is used. 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 a plurality of organic solvents and using them as mixed organic solvents, the bonding aid is dried immediately after application to the bonding site in consideration of the temperature environment and working environment where the bonding aid is used. There is an advantage that the drying time can be adjusted as appropriate so as not to miss.

  Here, the blending ratio of the component (A) and the component (B) is such that the content of the component (A) is 1% by weight or more and 50% by weight or less, from the viewpoint of obtaining high bonding strength. ) The content of the component is preferably in the range of 50 wt% to 99 wt%.

  Preferably, the content of the component (A) is 5% by weight or more and 30% by weight or less, the content of the component (B) is 70% by weight or more and 95% by weight or less, more preferably, the content of the component (A) It is preferable that the content is in the range of 5 wt% to 15 wt%, and the content of the component (B) is in the range of 85 wt% to 95 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). There is a tendency to become. On the other hand, when the content of the component (A) is less than 1% by weight and the content of the component (B) exceeds 99% by weight, the bonding strength of the polyamide resin integrated molded product tends to decrease.

  The joining aid may be produced using any production method as long as it can uniformly dissolve or disperse the component (A) in the component (B), and is particularly limited. It is not a thing.

  It should be noted that the above-mentioned polyamide resin, dye, thickener, antioxidant, etc. may be added to the bonding aid as long as the surface modifying 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.

  Here, according to this production method, a polyamide resin integrated molded article having a higher bonding strength can be obtained in a shorter bonding time than in the prior art. The reason is presumed as follows.

  That is, when the above-mentioned 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 surface-modified and chemically activated by the reducing action of the component (A). When the activated bonding sites are welded to each other, in the process where the polyamide resin in the molten state is recrystallized, the two are firmly bonded mainly by chemical bonds and integrated.

  Moreover, since it is not necessary to heat and melt the bonding site surface excessively in order to obtain high bonding strength, the carbonization of the polyamide resin hardly occurs. For this reason, the carbonized portion is unlikely to intervene at the bonding interface, and the chemical bond is hardly inhibited. In addition, a remelted and resolidified layer having poor strength is hardly generated.

  Therefore, according to this production method, it is presumed that a polyamide resin integrated molded article having high bonding strength and excellent bonding reliability can be obtained even with a bonding time shorter than the conventional one.

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

(Manufacture of polyamide resin integral molded product according to this example)
A polyamide resin integrated molded product (hereinafter referred to as “integrated molded product”) was manufactured by the following procedure using a hot plate welding method. First, the outline of the manufacturing method of the integrally molded product using the hot plate welding method will be described with reference to FIGS.

  As shown in FIG. 1, the molded product 10 and the molded product 11 are both made of polyamide resin and manufactured in advance by injection molding. The molded product 10 and the molded product 11 have joint end surfaces 12 and 13, respectively. When these joint end surfaces 12 and 13 are joined to each other, the hollow molded product 14 (FIG. 5) is finally formed. Is manufactured). Although ribs 15 and 16 are provided around the joint end surfaces 12 and 13 of the molded product 10 and the molded product 11, the ribs 15 and 16 may be basically omitted in the present invention.

  In FIG. 1, the molded product 10 and the molded product 11 are respectively held by an upper jig 17 and a lower jig 18 of a hot plate welding apparatus. The upper jig 17 and the lower jig 18 can be changed in relative distance from each other, and are added in a state where the joining end surface 12 of the molded article 10 and the joining end face 13 of the molded article 11 are aligned. It can be pressurized.

  Further, on the right side of the upper jig 17 and the lower jig 18, a metal hot plate 19 is held at a retracted position. In this state, a bonding assistant having a component ratio described later is applied to the bonding end surface 12 of the molded product 10 and / or the bonding end surface 13 of the molded product 11.

  Next, as shown in FIG. 2, the hot plate 19 heated to a temperature at which the polyamide resin dissolves is moved between the joint end surface 12 of the molded product 10 and the joint end surface 13 of the molded product 11. Next, the upper jig 17 and the lower jig 18 are moved in directions in which their relative positions approach each other. Thereby, the polyamide resin of the joining end surface 12 and the polyamide resin of the joining end surface 13 are heated and melted at a predetermined temperature for a predetermined time.

  Next, as shown in FIG. 3, the upper jig 17 and the lower jig 18 are moved in directions in which the relative positions of the upper jig 17 and the lower jig 18 are separated from each other, and the hot plate 19 is retracted to the original position.

  Next, as shown in FIG. 4, the upper jig 17 and the lower jig 18 are moved again in a direction in which the relative positions of the upper jig 17 and the lower jig 18 approach each other, so that the joint end surface 12 of the molded product 10 and the joint end surface 13 of the molded product 11 are obtained. Are welded together at a predetermined pressure for a predetermined time.

  Next, the polyamide resin integrated molded product 14 in which the molded product 10 and the molded product 11 are welded and integrated is cooled by a cooling means (not shown).

  Next, as shown in FIG. 5, the upper jig 17 and the lower jig 18 are moved in directions in which their relative positions are separated from each other. Thereby, the integrally molded product 14 is released from both the jigs 17 and 18, and the hollow tank-shaped integrated molded product 14 is obtained.

  Here, in the manufacture of the integrally molded product according to this example, the heating time for heating the polyamide resin was set to two types of 10 seconds and 17.5 seconds.

  Further, nylon 6 (“Amilan CM1026” manufactured by Toray Industries, Inc.) was used as the material of the molded product 10, and nylon 6 (“Amilan CM1011G30” manufactured by Toray Industries, Inc.) reinforced with glass fiber was used as the material of the molded product 11. .

  In addition, “SLC4530” manufactured by Unitech Co., Ltd. was used as the hot plate welding apparatus. At this time, the temperature of the hot plate was set to 502 to 512 ° C on the upper side and 503 to 513 ° C on the lower side. The set pressure during pressure bonding was 0.2 MPa, and the set pressure during cooling was 0.3 MPa.

  In addition, the joining aid includes 7.5% by weight of 1,3 dihydroxybenzene, 7.5% by weight of 3,5 dihydroxybenzoic acid as component (A), and 42.5% of methanol as component (B). Predetermined amounts were weighed so that the weight percent and isopropyl alcohol would be 42.5 weight percent, and those obtained by thoroughly mixing them using a stirrer were used.

  1,3 dihydroxybenzene, 3,5 dihydroxybenzoic acid, methanol and isopropyl alcohol are all manufactured by Wako Pure Chemical Industries, Ltd.

(Manufacture of polyamide resin integrated molding according to comparative example)
On the other hand, an integral molded product according to the comparative example was produced in the same manner as the integral molded product according to the example except that the joining aid was not applied in the production of the integral molded product according to the above example.

(Evaluation test of integral molding)
With the integrally molded product manufactured as described above, the breaking strength by a pressure test was measured. At this time, a hydraulic pressure type manual booster pump was used as the pressure resistance test device, and the peak strength at which the pressure was broken in about 3 minutes was measured. The number of samples was N = 3.

  Moreover, the joint part of the molded product was cut into a strip shape, and the maximum tensile force by a tensile test was measured. At this time, a universal material testing machine (INSTRON 4505) was used as the tensile test apparatus. The tensile test speed was 5 mm / min, and the number of samples was N = 5.

  Moreover, the joining area of the joined part was measured, and the breaking strength by the tensile test was calculated.

  In the evaluation test, the fracture strength by the pressure test was 0.8 MPa or more, the maximum tensile force was 80 kgf or more, and the fracture strength by the tensile test was 22 MPa or more.

  The test results are shown in Table 1. In the table, “OK” is indicated as “OK” and “NG” is indicated as “FAIL”.

  When all the evaluation items (breaking strength by pressure resistance test, maximum tensile force, breaking strength by tensile test) are compared with the integrally molded product according to the present example and the integrally molded product according to the comparative example, according to this example It can be seen that the integrally molded product satisfies the above-mentioned criteria even with a short heating time (10 seconds) as well as with a long heating time (17.5 seconds).

  On the other hand, the integrally molded product according to the comparative example satisfies the above-mentioned standard for a long heating time (17.5 seconds), but does not satisfy the above-mentioned standard for a short heating time (10 seconds). .

  Moreover, it turns out that the integral molded product which concerns on a present Example has high joint strength even if it is a short heating time compared with the integral molded product which concerns on a comparative example.

  Therefore, according to the manufacturing method of the integrally molded product according to the present embodiment, it is possible to manufacture an integrally molded product having a high bonding strength even when the heating time is shorter than the conventional one. Therefore, manufacturing cycle time can be shortened and productivity can be improved. In addition, in order to obtain high bonding strength, the time for heating and melting the polyamide resin can be shortened, so that carbonization of the polyamide resin and generation of a remelted and resolidified layer can be suppressed as much as possible.

  Moreover, when it sees about the fracture strength by a tension test, the direction of the integrally molded product (heating time 10 seconds) which concerns on a present Example is the tensile test rather than the integrally molded material (heating time 17.5 seconds) which concerns on a comparative example. The value of fracture strength due to is large.

  That is, it can be seen that according to the method of manufacturing an integrally molded product according to the present example, an integrally molded product having a high bonding strength can be obtained even with a smaller bonding area. Therefore, it is not necessary to form a joining margin by increasing the thickness of the joining end face, thereby ensuring the joining strength, so that an integrally molded product having excellent shape flexibility can be manufactured.

  Furthermore, it is possible to suppress as much as possible the protruding portion that occurs when crimping the joining end faces, so there is no need to provide ribs around the joining end faces so that they are not exposed from the outer surface of the product, and an integral molded product with excellent appearance quality can be obtained. Can be manufactured.

(Evaluation of integrally molded products manufactured using other bonding aids)
Next, (A) component is 1,2,3 trihydroxybenzene, 3,5 dihydroxybenzoic acid, 3,4,5 trihydroxybenzoic acid, 1,3 dihydroxybenzene, (B) component is methanol, isopropyl Examples were obtained in accordance with the same procedure as described above, except that a predetermined amount of alcohol was weighed so as to have the composition shown in Tables 2 to 6 described later, and a bonding aid obtained by thoroughly mixing these using a stirrer was used. The integrally molded product according to 1 to 30 was manufactured. Moreover, the integral molded product which concerns on the comparative example 1 was manufactured like the integral molded product which concerns on an Example except not having apply | coated the said joining adjuvant.

  Incidentally, 1,2,3 trihydroxybenzene and 3,4,5 trihydroxybenzoic acid are manufactured by Wako Pure Chemical Industries, Ltd.

  Subsequently, the fracture strength by the pressure test was measured with the integrally molded product according to Examples 1 to 30 and the integrally molded product according to Comparative Example 1. In this pressure resistance test, those with a fracture strength of less than 0.8 MPa are regarded as rejected (x), those with 0.8 MPa or more and less than 1.1 MPa are accepted (B), and those with 1.1 MPa or more are accepted (A ). Tables 2 to 6 show the composition of the bonding aid used and the test results of the integrally molded products according to Examples 1 to 30.

  As shown in Tables 2 to 6, each of the integrally molded products according to Examples 1 to 30 has sufficient bonding strength with a heating time of about 10 seconds as compared with the integrally molded product according to Comparative Example 1. You can see that

  Next, FIG. 6 is a cross-sectional photograph in which the joint portion of the integrally molded product according to Comparative Example 1 is cut. FIG. 7 is a cross-sectional photograph of the joint part of the integrally molded product according to Example 15 cut. According to FIGS. 6 and 7, it can be seen that the molded products 10 and 11 are joined together in both the integrally molded products.

  Moreover, it turns out that the protrusion part 20 is hardly formed in the integral molded product which concerns on Example 15 compared with the integral molded product which concerns on the comparative example 1. FIG.

  FIG. 8 is a cross-sectional photograph of the joined portion after the destructive test of the integrally molded product according to Comparative Example 1. FIG. 9 is a cross-sectional photograph of the joined portion after the destructive test of the integrally molded product according to Example 15. 8 and 9, it can be seen that it is the interface of the protruding portion 20 that is the remelted and resolidified layer that is broken in both of the integrally molded products.

  In consideration of the fact that the maximum tensile strength of Example 15 was better than that of Comparative Example 1, this protruding portion 20 was a remelted and resolidified layer in which the polyamide resin on the molded body side was melted and resolidified. It is thought that.

  This remelted and resolidified layer is the most heated and melted part in the joining process, and a part is considered to be carbonized by excessive heat.

  For this reason, it is considered that the strength of the joint portion of the obtained integrally molded product is lowered by the presence of the carbonized portion at the joint interface. In general, the polymer remelting / solidifying layer also has some molecular breakage due to thermal decomposition, which is considered to be considerably reduced compared to the original strength of the resin.

  However, according to this manufacturing method, the cycle time can be shortened, the joining area can be reduced, and joining with a small amount of deformation can be performed, so that the occurrence of the protruding portion 20 can be suppressed as much as possible. Therefore, it was confirmed from the Examples that the joint strength of the obtained integrally molded product is increased.

  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 integrated molded product is produced by using the hot plate welding method has been described, but other than that, ultrasonic welding, vibration welding, hot air welding, high frequency welding, laser welding, electromagnetic It is also possible to produce a polyamide resin integral molded article by welding the bonded portions of the polyamide resin molded article to each other using the above-mentioned bonding aid using induction welding, infrared welding or the like.

It is the figure which showed the state by which each molding is hold | maintained at the upper side jig | tool and lower side jig | tool of a hot plate welding apparatus. It is the figure which showed the state which made a hot plate adjoin between the joining end surfaces of each molding, and heat-melted the polyamide resin of a joining end surface. It is the figure which showed the state which retracted the hot plate to the original position. It is the figure which showed the state which crimped | bonded and welded each molding. It is the figure which showed the state by which the hollow tank-shaped polyamide resin integral molding was released from each jig | tool. 5 is a cross-sectional photograph of a joint part of an integrally molded product according to Comparative Example 1 cut. It is the cross-sectional photograph which cut | disconnected the junction part of the integrally molded product which concerns on Example 15. FIG. It is the cross-sectional photograph which cut | disconnected the junction part after the destructive test of the integrally molded product which concerns on the comparative example 1. FIG. It is the cross-sectional photograph which cut | disconnected the junction part after the destructive test of the integrally molded product which concerns on Example 15. FIG.

DESCRIPTION OF SYMBOLS 10 Molded product 11 Molded product 12 Joint end surface 13 Joint end surface 14 Polyamide resin integral molded product 15 Rib 16 Rib 19

Claims (5)

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;
Heating and melting the polyamide resin on the surface of the bonding site;
A step of crimping and welding the bonding sites to each other;
Cooling the welded and integrated polyamide resin integral molded product,
The bonding aid is
As component (A), 1,2 dihydroxybenzene, 1,3 dihydroxybenzene, 1,4 dihydroxybenzene, 2,3 dihydroxybenzoic acid, 2,4 dihydroxybenzoic acid, 2,5 dihydroxybenzoic acid, 2,6 dihydroxybenzoic acid Acid, 3,4 dihydroxybenzoic acid, 3,5 dihydroxybenzoic acid, 1,2,3 trihydroxybenzene, 1,2,4 trihydroxybenzene, 1,3,5 trihydroxybenzene, 2,3,4 trihydroxy At least one compound selected from benzoic acid, 2,4,6 trihydroxybenzoic acid, 3,4,5 trihydroxybenzoic acid, and hydrates thereof (provided that 1,3 dihydroxybenzene, 3, 5 dihydroxybenzoic acid and at least one compound selected from these hydrates are excluded)
(B) The manufacturing method of the polyamide resin integrated molding characterized by including the organic solvent which can melt | dissolve or disperse | distribute said (A) component as a component.   2. The polyamide resin according to claim 1, wherein the content of the component (A) is 1 wt% or more and 50 wt% or less, and the content of the component (B) is 50 wt% or more and 99 wt% or less. A method for producing an integrally molded product.   The method for producing an integrally molded polyamide resin product according to claim 1 or 2, wherein the component (B) is a mixed organic solvent in which a plurality of types of the organic solvent are mixed. The heating and melting of the polyamide resin, any one of claims 1 to 3, characterized in that by bringing close or contacting the plate-like member heating the polyamide resin to the meltable temperature to the junction surface The manufacturing method of the polyamide resin integral molded product as described in any one of. A polyamide resin integral molded product produced by the method for producing a polyamide resin integral molded product according to any one of claims 1 to 4.