JP2019137761A - Composition for casting molding - Google Patents

Abstract

To provide a composition for casting molding that comprises an ultraviolet-curable resin suitable for the handicrafts of self-making accessories such as brooches and small articles, has excellent curability, has high hardness while suppressing the warpage of a cured product, and has excellent moldability in a casting die.SOLUTION: A composition for casting molding contains a vinyl ether resin (A), an acrylate resin (B), a reactive diluent (C), and a photopolymerization initiator (D).SELECTED DRAWING: None

Description

  The present invention relates to a casting mold composition which is an ultraviolet curable type and has high hardness and little warpage and is excellent in moldability.

  Acrylic photocurable resins are used in many fields in order to give special performance to the surface of plastic films and plastic moldings. For example, hard coat films that are coated on a PET (polyethylene terephthalate) film and given high hardness are used in large quantities in touch panel products, and adhesive films that give viscosity to the film are flat panel display products that are final products. In addition, it is also used as a protective film in the manufacturing process.

  It is used as a resin for making accessories such as brooches and small items by making use of the hardness and transparency of acrylic resin even outside the field of applying special performance by applying a thin film on the plastic surface (Patent Literature) 1). In the past, the applicant has reported that a bifunctional urethane (meth) acrylate resin having a polyether skeleton number average molecular weight of 1,000 to 7,000, a monofunctional methacrylate monomer, an aromatic acrylate monomer, or a fat having no polar group. Invented a composition comprising a group acrylate monomer and a photopolymerization initiator (Patent Document 2). The present invention was excellent in that it was sufficiently cured without leaving any stickiness or the like even with a black light source, and was less susceptible to deformation or yellowing due to curing shrinkage. However, since this composition has a relatively low hardness, there is room for improvement in this respect.

Japanese Patent Laid-Open No. 10-264184 JP 2017-43703 A

  The problem of the present invention is an ultraviolet curable resin suitable for handicrafts that make accessories such as brooches and small items, and has excellent curability, and has a high hardness and little warpage of the cured product, and is a cast mold. The object of the present invention is to provide a casting composition having excellent moldability.

  The invention of claim 1 provides a casting composition comprising a vinyl ether resin (A), an acrylate resin (B), a reactive diluent (C), and a photopolymerization initiator (D).

The invention according to claim 2 provides the composition for casting mold according to claim 1, wherein the vinyl ether resin (A) has a urethane bond.

Moreover, invention of Claim 3 provides the composition for casting molds of Claim 1 or 2 characterized by the said acrylate resin (B) being a urethane (meth) acrylate oligomer.

The composition of the present invention is excellent in curability, has a high hardness, has little warpage of the cured product, and is excellent in moldability with a casting mold, and is suitable for handicraft applications such as making brooches and accessories. It is useful as a suitable UV curable casting composition.

The composition of the ultraviolet curable resin composition of the present invention is a vinyl ether resin (A), an acrylate resin (B), a reactive diluent (C), and a photopolymerization initiator (D). In the present specification, (meth) acrylate includes both acrylate and methacrylate.

The vinyl ether resin (A) used in the present invention is one of the main components constituting the cured film and is a resin having both a highly reactive alkene group and an ether group that is a bending component. For example, by reacting polyisocyanate with a vinyl ether having a hydroxyl group, a vinyl ether resin having a urethane bond having an elastic structure in the molecule can be obtained. Examples of the polyisocyanate to be reacted include hexamethylene diisocyanate, isophorone diisocyanate (hereinafter referred to as IPDI), dicyclohexylmethane diisocyanate, hydrogenated tolylene diisocyanate, and the like. Among these, IPDI which hardly yellows is preferable. In particular, a vinyl ether resin obtained by reacting 2-hydroxyethyl vinyl ether (hereinafter referred to as HEVE), 4-hydroxybutyl vinyl ether (hereinafter referred to as HBVE), or diethylene glycol monovinyl ether (hereinafter referred to as DEGV), which is a monovinyl ether, with IPDI is suitable with high reactivity. It is particularly preferable because a cured film having excellent elasticity can be obtained.

As a compounding quantity of (A) with respect to the whole composition, 15 to 60 weight% is preferable and 20 to 55 weight% is still more preferable. It becomes possible to suppress the curvature of hardened | cured material by setting it as 15 weight% or more, and can ensure sufficient reactivity by setting it as 60 weight% or less.

The acrylate resin (B) used in the present invention is a main component constituting the cured film as in (A), and those having reactive functional groups include urethane (meth) acrylate and epoxy (meth) acrylate. , Polyester (meth) acrylate, polycarbonate (meth) acrylate, and the like, which can be used alone or in combination of two or more.

Among these, an oligomer of urethane (meth) acrylate having both hardness and moderate elasticity is preferable. Urethane (meth) acrylate is produced, for example, by adding (meth) acrylate to the end of a compound obtained by addition reaction of polyol and diisocyanate, and has 2 to 6 (meth) acryloyl groups in the molecule. is there. When the number of functional groups is 1, the reactivity during polymerization is low and the molecular weight does not increase. When the number of functional groups exceeds 6, the warpage of the cured product tends to increase.

The number average molecular weight of the (B) is preferably an oligomer having a molecular weight of 500 to 30,000, and more preferably 1,000 to 10,000. When the molecular weight is less than 500, the resulting molded product has a small cohesive force and becomes brittle. When the molecular weight exceeds 30,000, the viscosity becomes high and the work becomes difficult, and the curability also decreases. The number average molecular weight (hereinafter referred to as “Mn”) was calculated by measuring the molecular weight in terms of standard polystyrene by gel permeation chromatography using a tetrahydrofuran solvent in a styrene divinylbenzene-based column.

The blending amount of the (B) with respect to the entire composition is preferably 3 to 50% by weight, and more preferably 5 to 40% by weight. When it is 3% by weight or more, sufficient curability can be ensured, and when it is 50% by weight or less, it is possible to control the viscosity suitable for workability.

  The reactive diluent (C) used for this invention plays the role which improves the reactivity while reducing the viscosity of said (A) and (B), improving workability | operativity. The number of functional groups may be monofunctional or polyfunctional, and may be used alone or in combination of two or more.

As an example of the (C), a (meth) acrylate monomer is preferable. Monofunctional (meth) acrylate monomers include alkyl (methyl) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, cyclohexyl (meth) acrylate, octyl (Meth) acrylate, ethylhexyl (meth) acrylate is aromatic, benzyl (meth) acrylate, phenoxyethyl acrylate is 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meta ) Acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate are those containing amino groups (meth) acrylamide, N, N-dimethyl (meth) acrylic Amide, N, N-diethyl (meth) acrylamide, N-isopropyl (meth) acrylamide, and acryloylmorpholine are dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, dicyclo Examples include pentanyl (meth) acrylate and isobornyl (meth) acrylate. Among these, acryloylmorpholine having low skin irritation and low vapor pressure is preferable.

Moreover, as a bifunctional (meth) acrylate monomer, (poly) ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, Dipropylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, 1.4-butanediol di (meth) acrylate, 4.6-hexanediol di (meth) acrylate, 1.9-nonanediol di ( And (meth) acrylate, 1.10-decanediol di (meth) acrylate, pentaerythritol di (meth) acrylate, isocyanuric acid EO-modified triacrylate, and the like. Among these, (poly) ethylene glycol di (meth) acrylate having good compatibility with (A) and (B) and low viscosity, and isocyanuric acid EO-modified diacrylate having low skin irritation are preferable.

Further, tri- or more-functional (meth) acrylate monomers include trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol tri (meth) acrylate, isocyanuric acid EO-modified triacrylate, trimethylolpropane tetra (Meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate and the like. Among these, isocyanuric acid EO-modified triacrylate having good compatibility with (A) and (B) and low skin irritation is preferable.

As an example of the (C), in addition to the (meth) acrylate monomer, a vinyl ether monomer having no urethane bond in the molecule other than the above (A) is also suitable. Examples of monovinyl ether monomers having one vinyl group are HEVE, HBVE, DEGV, and hydroxypropyl vinyl ether, and divinyl ethers having two vinyl groups are ethylene glycol divinyl ether and triethylene glycol divinyl ether. Examples of one or more vinyl ethers include trimethylol ethane trivinyl ether, trimethylol propane trivinyl ether, ditrimethylol propane tetravinyl ether, dipentaerythritol pentavinyl ether, and the like, which can be used alone or in combination of two or more. Among these, from the viewpoint of reducing warpage of the cured product, trifunctional or less is preferable, and bifunctional divinyl ether is more preferable.

The blending amount of the (C) with respect to the entire composition is preferably 20 to 50% by weight, more preferably 30 to 40% by weight. When the content is 20% by weight or more, sufficient reactivity can be secured, and when the content is 50% by weight or less, the viscosity can be controlled to be suitable for workability.

  The photopolymerization initiator (D) used in the present invention may be a general-purpose photopolymerization initiator because radicals are generated by irradiation with ultraviolet rays or electron beams, and the radicals trigger a polymerization reaction. By arbitrarily selecting the light absorption wavelength of the polymerization initiator, curability can be imparted over a wide wavelength range from the ultraviolet region to the visible light region. Specifically, 2-hydroxy-1- {4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl] phenyl} -2-methyl-propan-1-one, 1-hydroxy-cyclohexyl-phenyl -Ketone, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, 2-hydroxy-2-methyl-1-phenyl-propane-1- ON, 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one, and the like can be used alone or in combination of two or more. Among these, it is preferable that the cured product contains an α-hydroxyacetophenone system that hardly yellows and an acyl phosphine oxide system that absorbs at a long wavelength and has excellent internal curability.

The blending amount of (D) is preferably 0.5 to 30 parts by weight and more preferably 1 to 10 parts by weight with respect to 100 parts by weight of the total of the components (A), (B) and (C). When it is 0.5 parts by weight or more, sufficient curability can be secured, and when it is 30 parts by weight or less, excessive heat generation can be prevented.

The viscosity of this composition at 25 ° C. is preferably 500 to 30000 mPa · s, and more preferably 800 to 20000 mPa · s. When the pressure is 500 mPa · s or more, the workability is improved and the casting work is facilitated, and when it is 30000 mPa · s or less, the reproducibility of the casting mold and the bubble removal are improved.

In the composition of the present invention, a plasticizer, an antioxidant pigment, a dye, a light stabilizer, a photosensitizer, an antifoaming agent, a thickener, an ultraviolet absorber, and a wetting agent are added as necessary as long as the performance is not impaired. Various additives such as property modifiers may be included.

  EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated in detail, a specific example is shown and it does not specifically limit to these. In addition, when there is no description, it measured on the conditions of 25 degreeC relative humidity 65% of room temperature.

Example 1
A vinyl ether resin obtained by reacting IPDI and HBVE as (A) is used for a light-shielding bottle, and RUA-089 (Asia Kogyo Co., Ltd., urethane acrylate, Mn3,600, 5-functional) is used as (B). Aronix M-315 (manufactured by Toagosei Co., Ltd., isocyanuric acid EO-modified di- and triacrylate) and Aronix M-240 (manufactured by Toagosei Co., Ltd., PEG # 200 diacrylate) as a photopolymerization initiator (D) Omnirad 184 (iGM) (A-hydroxyacetophenone system) and OmniradTPOH (iGM, acylphosphine oxide system) are added in the amounts shown in Table 1, and stirred using a defoaming machine until uniform, the resin composition of Example 1 Adjusted.

Examples 2-8
In addition to the materials used in Example 1, a vinyl ether resin obtained by reacting IPDI and HEVE and a vinyl ether resin obtained by reacting IPDI and DEGV as (A), and SUA-023 (manufactured by Asia Kogyo Co., Ltd., Polyether-based urethane acrylate, Mn 1,000, bifunctional) using ACMO (KJ Chemicals, acryloylmorpholine) as (C), and uniformly using a stirring defoamer with the composition shown in Table 1 The resin composition of Examples 2-8 was prepared by stirring until it became.

Comparative Examples 1-3
In addition to the materials used in the examples, light acrylate PO-A (manufactured by Kyoeisha Chemical Co., Ltd., phenoxyethyl acrylate) is used as the (C), and until uniform using a stirring defoamer with the formulation shown in Table 1 The resin compositions of Comparative Examples 1 to 3 were prepared by stirring.

Preparation of cured product 3 g of a resin composition at room temperature was put into a silicone mold (manufactured by Elvert, silicone motif RSSD-2, 20 mm x 32 mm x t5 mm), and LED irradiation was performed from a height of 4 cm from the resin surface. It was cured by irradiating with a machine (Preampa Corporation, Pregel LED Light Suite, 10 W) for 2 minutes and further from the back surface for 1 minute. Thereafter, the cured product was taken out from the silicone mold and left at 23 ± 2 ° C. for 30 minutes to prepare.

Table 1

The evaluation method was as follows.

Viscosity: Cone plate type viscometer RC-550 manufactured by Toki Sangyo Co., Ltd., cone angle 3 ° R17.65, 25 ± 1 ° C., rotation speed 50 rpm for viscosity range 500 mPa · s or less, 500-2000 mPa · s 20 rpm 2000-5000 mPa · s was measured at 10 rpm, and 5000-10000 mPa · s was measured at 5 rpm.

  Curability: The degree of stickiness of the black light-irradiated surface of the cured product was confirmed by finger touch.

  Warpage: The four corners of the cured product and the distance from the ground contact surface were measured, and the average value was warped.

  Hardness: The irradiated surface of the cured product was measured with a D-type hardness meter (5 kg weighted).

The evaluation results of the examples are shown in Table 2.
Table 2

  The resin compositions of the examples were all good in curability, warpage, and hardness.

 On the other hand, Comparative Example 1 which does not contain (B) is inferior in curability, and Comparative Examples 2 and 3 which do not contain (A) are unsuitable for evaluation of warpage or hardness, and are not suitable for the present invention. It was.

The casting mold composition of the present invention is excellent in curability, has a high hardness, has little warpage of the cured product, and has excellent moldability in the casting mold, and is self-made with accessories such as brooches and small items. It is useful as an ultraviolet curable resin suitable for handicraft applications.

Claims (3)

A cast molding composition comprising a vinyl ether resin (A), an acrylate resin (B), a reactive diluent (C), and a photopolymerization initiator (D).   The composition for casting mold according to claim 1, wherein the vinyl ether resin (A) has a urethane bond. The casting composition according to claim 1 or 2, wherein the acrylate resin (B) is a urethane (meth) acrylate oligomer.