JP6544843B2 - Composite molded body - Google Patents

Description

  The present invention relates to a composite molded body in which a hard portion and a soft portion are integrated, and in particular to a composite molded body having high chemical resistance.

  BACKGROUND ART In recent years, use of wearable devices that can be compactly worn on the body is popular because of increasing health-consciousness and the spread of outdoor tastes. Wearable devices are equipped with electronic devices and electronic components for high-level sensing, so they are held in a hard case made of metal, resin, etc., while they are flexible when mounted on waterproof packing or a human body A flexible rubber-like material is also used for the purpose of giving a feeling of touch. In the past, these hard members and flexible members were often manufactured separately and used in combination, but in addition to the demand for further reductions in size and weight of wearable devices, comfort when worn on the human body, As the demand for waterproofness against rain, tap water, sweat and the like has increased, it has been required to integrate a hard member and a flexible member.

  Although not used for wearable devices, a technique in which a hard member and a flexible member are integrated with an adhesive is described, for example, in Japanese Patent Application Laid-Open No. 2014-231598 (Patent Document 1).

JP 2014-231598 A

  When we go back to the use of wearable devices, for example, when we try to wear wearable devices on the wrist of a person, the surface of the skin may be coated with cream such as hand cream or sunscreen, and these drugs are wearable Penetration into the flexible parts of the device is a problem. More specifically, these chemical components penetrate into the flexible member, and as a result, the adhesion between the flexible member and the hard member may be weakened, which may cause a problem that the flexible member may be peeled off. Moreover, even if it does not peel off immediately, the problem of peeling in a comparatively short time or becoming easy to peel with respect to external force arises.

  Therefore, in the present invention, in the case of a composite molded body in which a hard member and a flexible member are integrated, the adhesion with the hard member is hardly deteriorated even if the flexible member touches chemicals such as hand cream and sunscreen, etc. The object of the present invention is to obtain a composite molded body which is easy to maintain the

In order to solve the above-mentioned subject, the present invention is constituted as follows. That is, with respect to a composite molded body in which a hard portion made of hard resin and a soft portion made of soft resin are integrated, the soft portion is a binder made of organopolysiloxane having dimethyl silicone as a main skeleton and JIS K6253 specified. A comprises a silicone rubber powder having an A hardness of A20 to A80 and relatively softer than the binder , wherein the silicone rubber powder is contained in an amount of 10 to 30 vol% in a total of 100 vol% with the binder It is characterized by

  In the composite molded article of the present invention, a hard portion made of a hard resin and a soft portion made of a soft resin are integrated, and the soft portion is a binder made of organopolysiloxane having dimethylsilicone as a main skeleton and silicone rubber. Since the silicone rubber powder is constituted so as to be contained in 10 to 30% by volume in 100% by volume in total with the binder, the soft part can give a soft and comfortable feel, and this soft part However, the adhesion between the hard part and the soft part is less likely to be impaired even when touching with chemicals such as hand cream and sunscreen.

  The composite molded body can be configured such that the organopolysiloxane is a cured product of addition reaction type millable silicone or a cured product of peroxide curing type millable silicone. Since the organopolysiloxane of the composite molded body is configured as a cured product of addition reaction type millable silicone or a cured product of peroxide curable type millable silicone, chemicals such as hand cream and sunscreen are mixed by mixing with silicone rubber powder. It is easy to improve chemical resistance to

  The composite molded body can configure the thickness of the soft portion to 100 μm or more. Since the composite molded body has a thickness of 100 μm or more of the soft part, the penetration of the soft part can be suppressed even when the soft part touches chemicals such as hand cream and sunscreen, and the adhesion between the hard part and the soft part Hard to lose.

  In the composite molded body, the hard portion can be made of polyamide or polycarbonate. Since the hard portion of the composite molded body is made of polyamide or polycarbonate, these materials are relatively inexpensive and yet have adequate strength, and it is easy to improve the adhesion to the soft portion.

  The composite molded body can be configured to include an intermediate layer composed of a primer layer or an adhesive layer between the hard portion and the soft portion. Since the composite molded body is configured to have an intermediate layer composed of a primer layer or an adhesive layer between the hard portion and the soft portion, the adhesion between the hard portion and the soft portion can be enhanced. In addition, the components such as hand cream and sunscreen make it difficult for the primer layer and the adhesive layer to be corroded.

  According to the present invention, there is chemical resistance to chemicals such as hand cream and sunscreen, and the adhesion between the hard part and the soft part is hardly deteriorated even after being affected by the medicine, and the adhesiveness before being affected is It is a composite molded body that is easy to maintain.

It is a schematic cross section of the composite-shaped body of this invention. It is a schematic cross section of the modification of the composite molded object of this invention.

  The composite molded article of the present invention will be described in detail below. The same reference numerals are given to the same parts constituting the composite molded body, and the description of the overlapping functions, materials, manufacturing methods, effects and the like will be omitted.

  FIG. 1 shows a schematic cross-sectional view of a composite molded body 10 according to one embodiment. In this composite molded body 10, a hard portion 11 made of a hard resin and a soft portion 12 made of a soft resin are integrated, and can be used for wearable devices and the like.

  The hard part 11 fixes the substrate and other internal electrical devices or stabilizes the shape of the exterior product in the portion that becomes the core or outer frame of the housing for the wearable device or other exterior parts. And a member that does not deform easily. The material of the hard portion 11 is, for example, polypropylene resin, polyethylene resin, polyvinyl chloride resin, polystyrene resin, acrylonitrile styrene acrylate resin, acrylonitrile butadiene styrene resin, polyamide resin, polyacetal resin, polycarbonate resin, polyester resin, Examples thereof include rigid resins such as polybutylene terephthalate resin, polyphenylene oxide resin, polyphenylene ether resin, polyphenylene sulfide resin, polyurethane resin, epoxy resin, liquid crystal polymer, and composite resin of these. Among these, it is particularly preferable to use a polyamide resin or a polycarbonate resin. The polyamide resin and the polycarbonate resin are relatively inexpensive but have adequate strength, and the adhesion to the soft portion 12 is high. Moreover, it is a preferable aspect to use the hard resin which introduce | transduced the frame | skeleton of silicone type in order to raise the adhesive strength with respect to the soft part 12 as hard resin which comprises the hard part 11. FIG.

  The soft portion 12 is a portion that is laminated on the surface of the hard portion 11 to form the outer surface of at least a part of the composite molded body 10 and plays a role in providing the composite molded body 10 with a soft touch. When used in a wearable device, by avoiding the contact of the hard surface of the hard portion 11 with the human body and configuring the complex such that the soft portion 12 contacts the human body, the wearable device has excellent wearing feeling for human can do.

  The soft part 12 is a silicone composition having a rubbery elasticity including a binder 12a composed of an organopolysiloxane having dimethylsilicone as a main skeleton and a silicone rubber powder 12b, as schematically shown in a partially enlarged view of FIG. It is. The organopolysiloxane, which is the binder 12a, is solid but extremely flexible, has appropriate slipperiness, and exhibits the function of giving a human-friendly touch. The silicone rubber powder 12b has the same composition as the organopolysiloxane which is the binder 12a, but in a state of being randomly dispersed inside the soft portion 12 while maintaining the powdery body without being assimilated with the binder 12a. Exists.

  The shape of the silicone rubber powder 12b can be any shape such as spherical, scaly, acicular, fibrous, or indeterminate. Also, the particle size of the silicone rubber powder 12b can also be arbitrary. The hardness of the silicone rubber powder 12b is preferably A20 to A80 in terms of A hardness. If it is softer than A20, the tackiness of the silicone rubber powder may be increased and dispersion may be difficult. If it is harder than A80, the properties as a silicone resin may be enhanced and the chemical resistance may be reduced. Moreover, it is preferable that the silicone rubber powder 12b does not contain a plasticizer, and its hardness is soft compared with the hardness of the organopolysiloxane which is the binder 12a. It is because silicone rubber which does not contain a plasticizer and is relatively flexible can adsorb a larger amount of components of the hand cream and the sunscreen, so that the adhesion between the hard portion and the soft portion can be made less likely to be impaired.

  The addition amount of the silicone rubber powder 12b is 10 to 30% by volume in a total of 100% by volume of the binder 12a consisting of organopolysiloxane having dimethyl silicone as a main skeleton and the silicone rubber powder 12b. If the amount is less than 10% by volume, it is considered that the surface area of the interface between the binder 12a consisting of organopolysiloxane and the silicone rubber powder 12b is small, and the retention to hold the chemicals penetrating from the surface of the soft part 12 at this interface is reduced. The boundary between the hard portion 11 and the soft portion 12 is easily peeled off. On the other hand, if it is more than 30% by volume, the volume of the binder 12a is relatively reduced, and it is considered that chemicals and the like easily penetrate the soft portion 12, and the boundary between the hard portion 11 and the soft portion 12 is easily peeled.

  Organopolysiloxanes are known to have chemical resistance to certain chemicals, but are known to be easily swelled by aromatic compounds, and when soft part 12 is formed only from binder 12a consisting of organopolysiloxane When an aromatic compound adheres to the surface of the soft portion 12, it may penetrate into the interior and reach the interface between the hard portion 11 and the soft portion 12, which may cause peeling of the hard portion 11 and the soft portion 12. was there. However, by blending the silicone rubber powder 12b in the predetermined amount, the decrease in the adhesive strength of the soft portion 12 to the hard portion 11 can be suppressed, and the peeling can be effectively prevented.

  The thickness of the soft portion 12 is 100 μm or more, preferably 300 μm or more, and more preferably 500 μm or more. If it is less than 100 μm, the adhesive force with the hard part 11 is easily weakened by contacting with an aromatic chemical, and if it is 100 μm or more and less than 300 μm, the adhesive force may be weakened. If it is 300 μm or more and less than 500 μm, the adhesive force is weakened. This is because the deterrence effect is high, and the adhesive strength can be maintained at 500 μm or more. In addition, since the drug does not penetrate substantially from one side to the other of the soft part 12 if it is 500 μm or more, the upper limit is not limited, but providing the soft part 12 exceeding 5 mm is less necessary and wasteful become.

  The hardness of the soft portion 12 is preferably in the range of E15 to A80 in E hardness and A hardness specified in JIS K6253. If the hardness is less than E15, the durability as the exterior component may be insufficient. In addition, when the hardness exceeds A80, there is a risk that the high-quality touch unique to silicone may be lost.

  FIG. 2 shows a schematic cross-sectional view of a composite molded body 20 according to a modified embodiment. The composite molded body 20 is the same as the composite molded body 10 described above in that the hard portion 11 made of hard resin and the soft portion 12 made of soft resin are integrated, but the hard portion 11 and the soft portion are soft. It differs from the composite molded body 10 in that a primer layer or an adhesive layer (hereinafter, these layers are collectively referred to as an intermediate layer 13) is provided at the interface with the portion 12. The middle layer 13 which is a primer layer or an adhesive layer is located between the hard portion 11 and the soft portion 12 and has a function of enhancing the adhesion between the hard portion 11 and the soft portion 12.

  The adhesive layer is a layer formed by applying a so-called adhesive, and the adhesive layer itself is made of a polymer component having mechanical strength, and forms a third layer other than the hard portion 11 and the soft portion 12 It is a layer to gain. The layer thickness is preferably 1 to 50 μm. If it is thinner than 1 μm, it is difficult to obtain adhesion, and if it is thicker than 50 μm, further improvement in adhesion is not expected and it is likely to be wasted. As such an adhesive, a general adhesive used as an adhesive of a binder comprising an organopolysiloxane and a hard resin can be used. For example, synthetic rubbers, thermoplastic elastomers, urethane resins, epoxy resins, etc. Various adhesives such as polyamide resin, silicone, acrylic resin, vinyl acetate and cyanoacrylate can be mentioned.

  On the other hand, the primer layer is a so-called subbing layer, and the primer liquid is formed from a liquid having a low solid content, and usually has no adhesive property itself and is mainly formed by surface modification etc. The primer layer is also a layer comprising low molecular weight components. The layer thickness is preferably 0.1 μm to less than 1 μm. If it is thinner than 0.1 μm, it is difficult to obtain the coating effect, and even if it is thicker than 1 μm, it is difficult to expect more functional improvement than required. In addition, the layer thickness of these adhesive layers and primer layers is a preferable range, and when a primer layer is less than 1 micrometer, an adhesive layer may become 1 micrometer or more.

  In compositions such as a primer solution and a primer agent for forming a primer layer, a composition comprising a silane coupling agent-containing solution and other silane compounds, a titanate coupling agent-containing solution and other titanate compounds Can be mentioned. In addition to these, there are provided in the molecule a site to be bonded to the organopolysiloxane and a skeletal site in close contact with the hard resin forming the hard section 11, and one having affinity to the soft section 12 and the hard section 11 having different properties is used. be able to. Primers such as a silane coupling agent-containing layer, a silane compound-containing layer, a titanate coupling agent-containing layer, and a titanate compound-containing layer obtained by applying such a composition on the surface of the hard portion 11 or the soft portion 12 Layers can be suitably used.

  The primer layer obtained from the above composition often has a molecular weight smaller than that of the polymer, and has a small cohesive force. Therefore, when applied to the interface between general hard parts and soft parts, the effect of chemicals such as hand cream and sunscreen It is easy to receive. Therefore, in the composite molded article comprising the hard portion 11 and the soft portion 12 of the present invention to which such a primer layer is applied, the retention of the adhesive strength between the hard portion 11 and the soft portion 12 is excellent.

  The hard part 11 and the soft part 12 are integrally fixed, and the adhesive strength can achieve 15 N or more in the 180 degree peel test of JIS K 6854. In addition, the adhesive strength after carrying out a predetermined chemical resistance test is also strong, and the strength of 50% or more can be maintained as compared with the initial adhesive strength before the chemical resistance test.

  In order to manufacture the composite molded body 10, a hard resin is molded to prepare the hard portion 11 first. Next, the hard portion 11 is disposed in a mold, and the soft portion 12 is placed in the mold and solidified to integrally form the hard portion 11, thereby forming the composite portion in which the soft portion 12 is fixed to the hard portion 11. Get the body 10 Moreover, in order to manufacture the composite molded body 20, before injecting the composition to be the soft part into the mold, the primer or the adhesive to be the intermediate layer 13 is applied to the portion of the hard part 11 to which the soft part 12 adheres. By doing this, the composite molded body 20 can be obtained.

  The composite molded body 10, 20 thus obtained is obtained by adding each powder such as titanium oxide, magnesium oxide, silicone resin, gel method silica, precipitated silica, polyethylene or the like to a soft part consisting only of organopolysiloxane. Compared with a composite molded article using the soft part, the chemical resistance to an aromatic compound is improved, and the composite molded article which can suppress the decrease in the adhesion between the hard part and the soft part after touching the aromatic compound 10, 20.

  The present invention will be described in more detail based on examples (comparative examples).

  In order to determine the presence or absence of a phenomenon in which the soft part peels off the hard part when hand cream or sunscreen is attached to the surface of the soft part, for the composite molded article in which the hard part and the soft part are fixed, Composite molded bodies of samples 1 to 16 were prepared, and the adhesion between the hard part and the soft part was tested before and after placing the sample in a chemical atmosphere to evaluate the adhesion between the hard part and the soft part to the drug. did.

  <Preparation of sample>

  Composite molded bodies to be samples 1 to 16 shown below were produced.

  The sample 1 shape | molded the polyamide resin (66 nylon) in the magnitude | size of 20 mm x 70 mm x 1 mm, and produced the hard part. Subsequently, a primer solution containing a silane coupling agent and an acrylic ester dissolved in a solvent was applied to a width of 20 mm from the end of the hard portion, and a release film was disposed on the remaining portion. Then, this is placed in a mold, and a liquid composition for forming a soft part having a binder of millable addition reaction type mainly composed of a dimethyl silicone skeleton as a binder is injected into the mold and cured to have the same size as the hard part. After integrally molding a soft part having a thickness of 1 mm, the peelable film was removed. Thus, the hard part and the soft part were fixed in the range of 20 mm × 20 mm to which the primer was applied, and the 20 mm × 50 mm part on which the release film was disposed obtained a composite molded body in which the hard part and the soft part were not fixed. This was taken as sample 1.

  Samples 2 to 14 were prepared in the same manner as sample 1 except that the material of the soft part was changed to the materials and blending amounts shown in Table 1 below, and these were used as samples 2 to 14 and did. A sample containing "powder" in the composition was mixed with the powder in a binder and sufficiently stirred to form a liquid composition for forming a soft part.

  The sample 15 and the sample 16 produced the composite molded body by the same composition and method as the sample 3 except that the thickness of the soft part was changed to the thickness shown in Table 1 below. That is, in the sample 15, the thickness of the soft part was 0.6 mm, and in the sample 16, the thickness of the soft part was 0.3 mm.

Each material shown in the composition column of Table 1 is as follows.
“Silicone rubber” is a silicone rubber powder having a spherical shape with an average particle diameter of 2 μm and a hardness of A40 and a dimethyl silicone skeleton.
The “silicone resin” is a spherical silicone resin powder having an average particle diameter of 6 μm and siloxane bonds crosslinked in a network.
“Gel method silica” is a porous silica powder having an average particle diameter of 2.5 μm and a specific surface area of 50 to 350 m ² / g.
“Settled silica” is a porous silica powder having an average particle diameter of 2.8 μm and a specific surface area of 250 to 900 m ² / g.
"Titanium oxide" is an anatase-type titanium oxide powder having an average particle size of 0.15 μm.
"Magnesium oxide" is an amorphous magnesium oxide powder with an average particle size of 4.5 μm.
“Polyethylene” is a high molecular weight polyethylene powder having an average particle size of 30 μm, a spherical shape and a hardness of D65.

  <Various tests and evaluations for samples 1 to 16>

Chemical resistance test:
For each sample, a surface of the soft part is coated with ² g / 100 cm ^{2 of} Coppertone SPORT High Performance Accu Spray Broad Spectrum SPF 50 (registered trademark), which is a polyethylene bag (Unipack C-8, registered trademark) ) And allowed to stand at 23 ° C. for 100 hours. After leaving for 100 hours, the hard part and the soft part were peeled off, and after that, those which could not be subjected to the peeling test described later were described as "peeling" in the column of "adhesive strength after chemical resistance test" in Table 1.

Peeling test:
The 180 degree peeling test based on JIS K6854 was done about each sample. This peeling test was carried out without the chemical resistance test, and the result (N / cm) when the soft part was peeled from the hard part was described in the column of “initial adhesion” in Table 1. Moreover, the result (N / cm) of performing this peeling test after conducting the said chemical resistance test was described in the column of the "adhesion force after a chemical resistance test" of Table 1. However, this peeling test was not conducted for those in which the hard portion and the soft portion were peeled in the chemical resistance test. In addition, each test value is shown by three average values except the maximum value and the minimum value of the result of producing and testing five samples of each sample.

Adhesive strength maintenance rate:
The adhesive strength maintenance rate was calculated | required from the peeling test result before and behind the said chemical-resistance test. That is, the adhesion after the chemical resistance test is expressed as a percentage (%) with respect to the adhesion obtained without the chemical resistance test, and is described in the column of "adhesion maintenance ratio" in Table 1. did. After the chemical resistance test, the hard part and the soft part were exfoliated before conducting the exfoliation test and described as “0”.

chemical resistance:
For each sample, the influence of the chemical on the adhesion between the hard and soft parts is described in the "chemical resistance" column of Table 1. "X", adhesive strength maintenance rate is 50% because chemical resistance is bad if the peel resistance test does not peel off the hard part and the soft part after the chemical resistance test and the adhesive strength maintenance rate is less than 50%. Those with more than 70% are evaluated as “Δ” as chemical resistance is not bad and those with 70% or more of adhesive strength maintenance rate are evaluated as “O” as excellent in chemical resistance. , It described in the column of "chemical resistance" of Table 1.

  <Analysis of evaluation results>

  Looking at the above test results, samples 3-5, 13 other than samples 1, 2, 6-12, 14 which had poor chemical resistance when the thickness of the soft part was 1.0 mm, had an adhesion of 15 N / Among them, Sample 3 which was not inferior in chemical resistance is a soft part in which 10% by mass of silicone rubber powder is mixed with mirable addition reaction type silicone, which is cm or more and the adhesive strength maintenance rate is 50% or more. Similarly, Sample 13 in which the chemical resistance was not deteriorated was a soft part in which 10% by mass of silicone rubber powder was mixed with millable peroxide curable silicone. Moreover, the sample 4 and the sample 5 which became a result which is excellent in chemical resistance were those in which the soft part which contains 20 mass% or more of silicone rubber powder in millable addition reaction type silicone was formed.

  From the above, when 10% by mass or more of silicone rubber powder is contained in mirable addition reaction type silicone or millable peroxide curable silicone, the chemical resistance is improved, and when it is in 20% by mass or more, the chemical resistance becomes superior and soft It has been found that the addition of silicone rubber powder to the part is effective in reducing the decrease in adhesion to chemicals.

  13. Samples 1 and 12 which had poor chemical resistance did not have silicone rubber powder added, and in particular, for sample 12, the adhesion to the hard part was weak before the chemical resistance test, and 13. It peeled easily with a weak force of 8 N / cm. In addition, Samples 6 to 11 in which the chemical resistance was similarly poor were those to which powders of types other than silicone rubber powder were added. From the above results, it was found that even when powders such as silicone resin, gel method silica, precipitated silica, magnesium oxide and polyethylene were added to the binder, chemical resistance like silicone rubber powder could not be obtained.

  It was found that the samples 15 and 16, which had the same composition of the soft part and different thicknesses, were excellent in chemical resistance, and were excellent in chemical resistance even at least as thin as 0.3 mm, which is the thickness of the sample 16.

DESCRIPTION OF SYMBOLS 10 composite molded object 11 hard part 12 soft part 12a binder 12b silicone rubber powder 13 middle layer (primer layer or adhesive bond layer)

Claims (5)

In a composite molded body in which a hard portion made of hard resin and a soft portion made of soft resin are integrated,
The soft portion includes a binder made of organopolysiloxane having dimethyl silicone as a main skeleton, and a silicone rubber powder having an A hardness of A20 to A80 according to JIS K6253 and relatively softer than the binder. And the silicone rubber powder is contained in an amount of 10 to 30% by volume in a total of 100% by volume with the binder.
The composite molded body according to claim 1, wherein the organopolysiloxane is a cured product of addition reaction type millable silicone or a cured product of peroxide curing type millable silicone.
The composite molded body according to claim 1, wherein a thickness of the soft portion is 100 μm or more.
The composite molded article according to any one of claims 1 to 3, wherein the hard portion is made of polyamide or polycarbonate.
The composite molded body according to any one of claims 1 to 4, further comprising an intermediate layer comprising a primer layer or an adhesive layer between the hard portion and the soft portion.

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