JP5466464B2 - Resin composition for surface light emitter, molded body for surface light emitter, and surface light emitter - Google Patents

Description

  The present invention relates to a resin composition for a surface light emitter, a molded body for a surface light emitter, and a surface light emitter.

  Conventionally, as a light diffusing member such as a lighting cover and various signboards, a molded body of a light diffusing resin composition in which inorganic or organic fine particles are dispersed in a transparent resin has been widely used.

As such a light diffusing resin composition, for example, a material in which a light diffusing agent composed of transparent fine particles is dispersed in a transparent resin has been proposed (for example, see Patent Documents 1 and 2).
Specifically, regarding the relationship of the refractive index difference between the transparent resin and the light diffusing agent, 0.02 ≦ | Ns−Np | ≦ 0.1 and 4 ≦ d in the transparent resin (refractive index Ns). ≦ 10 μm (in Patent Document 2, the mixing rate of particles of 3 μm or less is 5%) A light diffusing resin composition in which a light diffusing agent composed of transparent fine particles (refractive index Np, average particle diameter d) is satisfied. Things are disclosed.

Further, a light diffusing resin composition in which a light diffusing agent comprising at least two components among SiO ₂ , CaCO ₃ and organic polymer fine particles having a specific particle diameter is uniformly mixed in a translucent (transparent) resin, and A light diffusing resin sheet material obtained by molding a resin composition is disclosed (for example, see Patent Document 3).

JP-A-60-139758 JP-A-60-184559 Japanese Patent Publication No.62-31741

In order to increase the light diffusibility in the molded article of the light diffusing resin composition described above, it is effective to add a large amount of the light diffusing agent comprising the transparent fine particles. However, when the addition amount of the light diffusing agent is increased, the light transmittance and the light emitting surface brightness are lowered.
In the above prior art, a light diffusing resin composition in which both light diffusibility and light transmissive characteristics are compatible has not been realized yet.

  In addition, the above-described molded body of the light diffusing resin composition can be used as a decorative display that emits surface light by irradiating, for example, an LED light in a direction parallel to the surface from the end surface of the molded body. However, it is demanded to realize high light diffusibility, enhance light transmittance, and improve light emitting surface luminance.

  Accordingly, an object of the present invention is to provide a resin composition having excellent light diffusibility and high light transmittance, a molded body for a surface light emitter formed from the resin composition, and a surface light emitter. .

As a result of intensive studies, the present inventors have established a numerical range of aromatic hydrocarbon content in a resin composition containing a block copolymer of a vinyl aromatic compound having a specific structure and a conjugated diene. The present invention has found that a resin composition having excellent light diffusibility and high light transmittance, a molded product for a surface light emitter obtained by molding the resin composition, and a surface light emitter having a high light emitting surface brightness can be obtained. It came to complete.
That is, the present invention is as follows.

[1]
It comprises a first polymer block A mainly composed of vinyl aromatic hydrocarbons and a first polymer block B mainly composed of conjugated dienes, and the vinyl aromatic hydrocarbon content is 20 to 40% by mass. A block copolymer (a), a second polymer block A mainly composed of vinyl aromatic hydrocarbons, and a second polymer block B mainly composed of conjugated dienes, A resin composition for a surface light emitter comprising a block copolymer (b) having a hydrogen content of 70 to 95% by mass and having a vinyl aromatic hydrocarbon content in the resin composition of 53% by mass or more. provide.

[2]
A molded product for a surface light emitter obtained by molding the resin composition for a surface light emitter according to the above [1] is provided.

[3]
The total light transmittance (T%) and haze value (H%) of a flat plate having a thickness of X mm measured according to JIS K7105 satisfy the following formulas (1) and (2), according to [2] above. A molded body for a surface light emitter is provided.
98- (98-T) / X> 89 (1)
2.5 <H / X <10 (2)

[4]
It has a polymer block phase mainly composed of vinyl aromatic hydrocarbons, and the polymer block phase mainly composed of vinyl aromatic hydrocarbons has a thickness of 0.2 μm or less. [2] A molded article for a surface light emitter according to [3] is provided.

[5]
A molded body for a surface light emitter according to any one of the above [2] to [4], comprising a base layer of a thermoplastic resin.

[6]
The surface light emitter molded body according to any one of [2] to [5], and a light source disposed to face at least one side end surface of the surface light emitter molded body. A surface light emitter that emits light by emitting light from the front side of the surface light emitter molded body when light is incident on a side end surface of the surface light emitter compact by the light source.

  ADVANTAGE OF THE INVENTION According to this invention, the resin composition which has the outstanding light diffusibility and high light transmittance, the molded object for surface light emitters which shape | molded the said resin composition, and the surface light emitter with a high light emission surface brightness are obtained.

Hereinafter, a mode for carrying out the present invention (hereinafter referred to as “the present embodiment”) will be described.
The present invention is not limited to the following description, and various modifications can be made within the scope of the gist thereof.

(Resin composition)
The resin composition of this embodiment consists of a block copolymer (a) and a block copolymer (b).
The block copolymer (a) has at least one first polymer block A mainly composed of vinyl aromatic hydrocarbon and at least one first polymer block B mainly composed of conjugated diene. And at least one of block copolymers having a vinyl aromatic hydrocarbon content of 20 to 40% by mass.
The first polymer block A mainly composed of the vinyl aromatic hydrocarbon is a copolymer block of a vinyl aromatic hydrocarbon and a conjugated diene having a vinyl aromatic hydrocarbon content of 50% by mass or more, and And / or a vinyl aromatic hydrocarbon homopolymer block.
The first polymer block B mainly composed of a conjugated diene is a copolymer block of a vinyl aromatic hydrocarbon and a conjugated diene and / or a conjugated diene in which the content of the conjugated diene compound exceeds 50% by mass. It is a compound homopolymer block.

The vinyl aromatic hydrocarbon content of the block copolymer (a) is 20 to 40% by mass as described above, and preferably 30 to 40% by mass.
When the vinyl aromatic hydrocarbon content of the block copolymer (a) is in the range of 20 to 40% by mass, excellent surface light emission is obtained when a surface light emitter is formed using a molded body of the resin composition. When the vinyl aromatic hydrocarbon content of the block copolymer (a) is in the range of 30 to 40% by mass, higher transparency can be obtained.

The block copolymer (b) contains at least one second polymer block A mainly composed of vinyl aromatic hydrocarbons and at least one second polymer block B mainly composed of conjugated diene. And at least one block copolymer having a vinyl aromatic hydrocarbon content of 70 to 95% by mass.
The second polymer block A mainly composed of the vinyl aromatic hydrocarbon is a copolymer block of a vinyl aromatic hydrocarbon and a conjugated diene having a vinyl aromatic hydrocarbon content of 50% by mass or more, and And / or a vinyl aromatic hydrocarbon homopolymer block.
The second polymer block B mainly comprising a conjugated diene is a copolymer block of vinyl aromatic hydrocarbon and conjugated diene and / or a conjugated diene in which the content of the conjugated diene compound exceeds 50% by mass. It is a compound homopolymer block.

The vinyl aromatic hydrocarbon content of the block copolymer (b) is 70 to 95% by mass as described above, and preferably 75 to 85% by mass.
When the vinyl aromatic hydrocarbon content of the block copolymer (b) is in the range of 70 to 95% by mass, excellent surface light emission is obtained when a surface light emitter is formed using a molded product of the resin composition. When the vinyl aromatic hydrocarbon content of the block copolymer (b) is in the range of 75 to 85% by mass, higher transparency can be obtained.

  In the resin composition of this embodiment, the blending amount of the block copolymer (a) is preferably 20% by mass to 60% by mass. Thereby, in the molded object for surface emitting bodies which shape | molded the resin composition of this embodiment, high transparency and the outstanding surface emitting property are obtained.

In the block copolymer (a) and the block copolymer (b), the first and / or second polymer block A mainly composed of vinyl aromatic hydrocarbon, the first and / or mainly composed of conjugated diene. When a random copolymer portion of vinyl aromatic hydrocarbon and conjugated diene exists in the second polymer block B, the copolymerized vinyl aromatic hydrocarbon is uniformly distributed in the polymer block. Or may be distributed in a taper (gradual decrease).
In addition, a plurality of portions where the vinyl aromatic hydrocarbon is uniformly distributed and / or a portion where the random aromatic portion is distributed in the tapered copolymer portion may coexist.

The first polymer block A and the second polymer block A, the first polymer block B and the second polymer block B constituting the block copolymer (a) and the block copolymer (b) May have the same or different molecular weight, composition, type, and the like.
The block copolymer (a) has a plurality of first polymer blocks A (or B), and the block copolymer (b) has a plurality of second polymer blocks A (or B). In some cases, they may be the same or different in molecular weight, composition, type, and the like.

The block copolymer (a) and the block copolymer (b) can be produced by a conventionally known method.
For example, Japanese Patent Publication No. 36-19286, Japanese Patent Publication No. 43-17879, Japanese Patent Publication No. 48-2423, Japanese Patent Publication No. 49-36957, Japanese Patent Publication No. 57-49567, Japanese Patent Publication No. 58-11446, etc. Can be mentioned.
Any of these methods is a method of block copolymerizing a conjugated diene and a vinyl aromatic hydrocarbon using an anionic initiator such as an organic lithium compound in a hydrocarbon solvent.

As a polymer structure of the block copolymer (a) and the block copolymer (b), for example,
A- (BA) _n , A- (BA) _n- B, B- (AB) _{n + 1}
The linear block copolymer represented by these is mentioned.
In the linear block copolymer formula, A is a polymer block mainly composed of vinyl aromatic hydrocarbons, and B is a polymer block mainly composed of conjugated dienes. The boundary between the A block and the B block does not necessarily have to be clearly distinguished. n is an integer of 1 or more, generally an integer of 1 to 5.
Moreover, as a polymer structure of a block copolymer (a) and a block copolymer (b),
[(A−B) _k ] _{m + 2} −X, [(A−B) _k −A] _{m + 2} −X, [(B−A) _k ] _{m + 2} −X,
[(B−A) _k −B] _{m + 2} −X
The radial block copolymer represented by these is mentioned.
In the formula of the radial block copolymer, A and B are the same as in the case of the linear block copolymer, k and m are integers of 1 or more, and are generally integers of 1 to 5. It is. X represents a residue of a coupling agent such as silicon tetrachloride or tin tetrachloride or a residue of an initiator such as a polyfunctional organolithium compound.
In the formulas representing the polymer structures of the block copolymer (a) and the block copolymer (b), the first polymer block A, the second polymer block A, and the first polymer block B are used. However, as described above, the molecular weight, the composition, the type, and the like may be the same or different from each other.
The various block copolymers described above may be used alone or in admixture of two or more.

Examples of the vinyl aromatic hydrocarbon include styrene, o-methylstyrene, p-methylstyrene, p-tert-butylstyrene, 1,3-dimethylstyrene, α-methylstyrene, vinylnaphthalene, vinylanthracene, 1, Examples include 1-diphenylethylene. In particular, styrene and p-methylstyrene are preferable.
These may be used alone or in combination of two or more.

The conjugated diene is a diolefin having a pair of conjugated double bonds, for example, 1,3-butadiene, 2-methyl-1,3-butadiene (isoprene), 2,3-dimethyl-1 , 3-butadiene, 1,3-pentadiene, 1,3-hexadiene and the like.
In particular, 1,3-butadiene and isoprene are preferable.
These may be used alone or in combination of two or more. When 1,3-butadiene and isoprene are used in combination, the amount of 1,3-butadiene is preferably 10% by mass or more when the sum of 1,3-butadiene and isoprene is 100% by mass, and 25% by mass. More preferably, it is more preferably 40% by mass or more. It is preferable that 1,3-butadiene is 10% by mass or more because thermal decomposition does not occur during molding and the molecular weight does not decrease.

Examples of the hydrocarbon solvent include aliphatic hydrocarbons such as butane, pentane, hexane, isopentane, heptane, and octane, cycloaliphatic hydrocarbons such as cyclopentane, methylcyclopentane, cyclohexane, methylcyclohexane, and ethylcyclohexane, benzene, Aromatic hydrocarbons such as toluene, ethylbenzene, xylene and the like can be mentioned.
These may be used alone or in combination of two or more.

An organolithium compound is used as the anionic initiator.
Examples of the organic lithium compound include an organic monolithium compound, an organic dilithium compound, and an organic polylithium compound in which one or more lithium atoms are bonded in the molecule. For example, ethyl lithium, n-propyl lithium, isopropyl lithium, n-butyl lithium, sec-butyl lithium, tert-butyl lithium, hexamethylene dilithium, butadienyl dilithium, isoprenyl dilithium and the like can be mentioned.
These may be used alone or in combination of two or more.

In the polymerization step of the block copolymers (a) and (b), adjustment of the polymerization rate, change of the microstructure of the polymerized conjugated diene part (ratio of cis, trans, vinyl), conjugated diene and vinyl aromatic hydrocarbon A polar compound or a randomizing agent may be used for the purpose of adjusting the reaction ratio.
Examples of polar compounds and randomizing agents include ethers such as tetrahydrofuran, diethylene glycol dimethyl ether and diethylene glycol dibutyl ether; amines such as triethylamine and tetramethylethylenediamine; thioethers, phosphines, phosphoramides, alkylbenzene sulfonates, potassium and the like. Examples thereof include sodium alkoxide.

The polymerization temperature of the block copolymers (a) and (b) is generally -10 ° C to 150 ° C, preferably 40 ° C to 120 ° C.
The time required for the polymerization varies depending on the conditions, but is usually within 48 hours and is preferably in the range of 1 to 10 hours.
The atmosphere of the polymerization system is preferably replaced with an inert gas such as nitrogen gas.
The polymerization pressure is not particularly limited as long as it is within the above-mentioned polymerization temperature range and is sufficient to maintain the monomer and solvent in the liquid layer.
It should be noted that impurities such as water, oxygen, carbon dioxide and the like that cause the catalyst and living polymer to be deactivated are not mixed in the polymerization system.

The block copolymers (a) and (b) can be used as hydrogenated products hydrogenated as necessary.
The hydrogenation catalyst for obtaining the hydrogenated products of the block copolymers (a) and (b) is not particularly limited, and examples thereof include the following hydrogenation catalysts that are conventionally known.
For example, (1) supported heterogeneous hydrogenation catalyst in which metals such as NI, Pt, Pd, and Ru are supported on carbon, silica, alumina, diatomaceous earth, etc. (2) NI, Co, Fe, Cr So-called Ziegler-type hydrogenation catalyst using a transition metal salt such as organic acid salt or acetylacetone salt and a reducing agent such as organoaluminum, and (3) so-called organic compounds such as organometallic compounds such as TI, Ru, Rh and Zr Examples thereof include homogeneous hydrogenation catalysts such as metal complexes.
Specifically, JP-B-42-8704, JP-B-43-6636, JP-B-63-4841, JP-B-1-37970, JP-B-1-53851, JP-B-2-9041 Can be used.

Preferred hydrogenation catalysts include mixtures with titanocene compounds and / or reducing organometallic compounds.
As the titanocene compound, compounds described in JP-A-8-109219 can be used. Specific examples thereof include (substitution) such as biscyclopentadienyl titanium dichloride and monopentamethylcyclopentadienyl titanium trichloride. And compounds having at least one ligand having a cyclopentadienyl skeleton, an indenyl skeleton, or a fluorenyl skeleton.
Examples of the reducing organometallic compound include organic alkali metal compounds such as organolithium, organomagnesium compounds, organoaluminum compounds, organoboron compounds, and organozinc compounds.

The hydrogenation reaction is generally carried out at 0 to 200 ° C., preferably 30 to 150 ° C.
The pressure of hydrogen used for the hydrogenation reaction is 0.1 to 15 MPa, preferably 0.2 to 10 MPa, more preferably 0.3 to 7 MPa.
The hydrogenation reaction time is usually 3 minutes to 10 hours, preferably 10 minutes to 5 hours.
For the hydrogenation reaction, a batch process, a continuous process, or the like can be applied, and a combination thereof may be used.

In the hydrogenated products of the block copolymers (a) and (b), the hydrogenation rate of the unsaturated double bond based on the conjugated diene can be arbitrarily selected according to the purpose and is not particularly limited.
In order to obtain a hydrogenated block copolymer with good thermal stability and weather resistance, it is hydrogenated in excess of 70% of the unsaturated double bonds based on the conjugated diene compound in the block copolymer. More preferably 75% or more, still more preferably 85% or more, and still more preferably 90% or more.
When obtaining a hydrogenated block copolymer having good thermal stability, the hydrogenation rate (hydrogenation rate) is 3 to 70%, preferably 5 to 65%, more preferably 10 to 60%.
The hydrogenation rate of the aromatic double bond based on the vinyl aromatic hydrocarbon in the copolymer is not particularly limited, but the hydrogenation rate is preferably 50% or less, more preferably 30% or less. More preferably, it is made 20% or less.
The above hydrogenation rate can be measured by a nuclear magnetic resonance apparatus (NMR).

When the hydrogenated block copolymers (a) and (b) are used, the content of the vinyl aromatic hydrocarbon polymer component in the hydrogenated product is the same as that described above for the block copolymer before hydrogenation. It can be grasped by the oxidative decomposition method.
The microstructure (ratio of cis, trans, vinyl) of the conjugated diene part of the block copolymers (a) and (b) can be arbitrarily changed by the use of the aforementioned polar compounds and the like, and there is no particular limitation.
In general, the vinyl bond amount can be set in the range of 5 to 90%, preferably 10 to 80%, more preferably 15 to 75%.
The vinyl bond amount is the total amount of 1,2-vinyl bond and 3,4-vinyl bond (however, when 1,3-butadiene is used as the conjugated diene, 1,2-vinyl bond amount) It is. The amount of vinyl bonds can be grasped by a nuclear magnetic resonance apparatus (NMR).

Each of the block copolymers (a) and (b) may be a mixture of two or more.
In addition, block copolymer (a) and (b) are mix | blended so that vinyl aromatic hydrocarbon component content in the resin composition of this embodiment may be 53 mass% or more. Thereby, in the molded object for surface emitting bodies which shape | molded the resin composition of this embodiment, high transparency and the outstanding surface emitting property are obtained.

[Method for producing resin composition]
The resin composition of the present embodiment can be obtained by kneading the block copolymers (a) and (b) described above.
As the kneading method, a conventionally known method can be applied.
For example, using a blender such as a Banbury mixer, a single screw extruder, a twin screw extruder, a kneader, a multi-screw extruder, etc., a method of melt kneading each component, a solvent after dissolving or dispersing and mixing each component, For example, a method of removing heat by heating. In particular, a melt kneading method using an extruder is suitable from the viewpoint of productivity and good kneading properties.
In addition, the resin composition of this embodiment is not limited only to the block copolymers (a) and (b) described above, and is predetermined according to various purposes within a range not impairing the effects of the present invention. Additives can be blended.
The additive is not particularly limited as long as it is generally used for blending resins and rubber-like polymers.
For example, inorganic fillers, pigments such as iron oxides, lubricants such as stearic acid, behenic acid, zinc stearate, calcium stearate, magnesium stearate, ethylene bisstearamide, mold release agents, paraffinic process oil, naphthenic process Oils, aromatic process oils, paraffins, organic polysiloxanes, mineralizers and other softeners / plasticizers, hindered phenol antioxidants, phosphorus heat stabilizers and other antioxidants, hindered amine light stabilizers, benzo Examples include triazole-based ultraviolet absorbers, flame retardants, antistatic agents, organic fibers, glass fibers, carbon fibers, reinforcing agents such as metal whiskers, and coloring agents.
These may be used alone or in combination of two or more.

[Molded body for surface light emitter]
The molded product for the surface light emitter of the present embodiment is a known molding method for the resin composition of the present embodiment described above, for example, injection molding, extrusion molding, blow molding, vacuum molding, inflation molding, film molding, sheet molding. It can be obtained by molding by the above method.
The molded product for a surface light emitter of the present embodiment has a total light transmittance (T%) and a haze value (H%) of a flat plate having a thickness of X mm measured in accordance with JIS K7105, using the following formula (1 ) And (2) are preferable.
98- (98-T) / X> 89 (1)
2.5 <H / X <10 (2)
The above formula (1) means that the total light transmittance of the flat plate molded body per 1 mm thickness exceeds 89%, and the above formula (2) indicates that the haze value of the flat molded body per 1 mm thickness is 2.5. Means more than 10% and less than 10%.
When the total light transmittance (T%) and the haze value (H%) satisfy the above formulas (1) and (2), the lateral end surface (parallel to the surface) of the flat molded body for the surface light emitter is obtained. When the green LED light is irradiated from (direction), the light emission area is sufficiently widened, and the color of the light emission state is clearly reflected and confirmed to be good.
The above formulas (1) and (2) are derived from experiments.
Actually, the total light transmittance when a 2 mm thick flat plate molded body is stacked is measured, and the total light transmittance at this time exceeds 80% as a pass line. Subtracting 2% of reflected light, it becomes 98- (98-80) × 1 mm thickness / 2 mm thickness = 89%, and the total light transmittance exceeds 89% when converted to 1 mm thickness of flat plate molded body. Was found to be a passing line.
The haze value is substantially proportional to the thickness.
From the above, based on the effect measured with a 2 mm-thick flat plate, an equation was derived so that the value would be expected when the thickness changed.

  When the molded product for a surface light emitter of the present embodiment has a polymer block phase mainly composed of vinyl aromatic hydrocarbons, the phase of the polymer block mainly composed of vinyl aromatic hydrocarbons is In any case, the thickness is preferably 0.2 μm or less. Thereby, high transparency and excellent light diffusibility can be obtained, and excellent surface light emission can be realized.

The thickness of the phase of the polymer block mainly composed of vinyl aromatic hydrocarbon can be measured by observation with a transmission electron microscope.
Specifically, a molded product for a surface light emitter is dyed by an osmium acid staining method, and then an ultrathin section having a thickness of about 8000 angstroms is cut out using a microtome and photographed with a transmission electron microscope.
The polymer block mainly composed of conjugated diene is selectively dyed and does not pass an electron beam so that it appears black, and the vinyl aromatic hydrocarbon block does not stain and appears white.
Polymer blocks mainly composed of vinyl aromatic hydrocarbons can take various shapes such as particles, rods, plates, meshes, or bent ones in the molded body. Thickness means the thickness of the thin direction in these various shapes. Specifically, it is the diameter if it is a perfect circle, the short diameter if it is oval, the length in the thickness direction if it is a rod, and the length in the thickness direction if it is a plate. If it is mesh-shaped, it is the thickness of the rod-shaped portion between the branch portions.
Moreover, when observing using a transmission electron microscope, it is necessary to observe from the direction which understands the thickness of the said phase. Except for the case where the molded body is non-oriented, the flow direction (MD) of the resin composition when producing the molded body, or the direction perpendicular to the flow direction (TD) of the resin composition is observed and measured. It is common to do.

The molded product for a surface light emitter of the present embodiment may be configured to include a base material layer of a thermoplastic resin.
By adopting a structure in which the molded body for the surface light emitter of the present embodiment is bonded to one side or both sides of the base layer of the thermoplastic resin, a large area can be easily produced.
The method for bonding the thermoplastic resin base material layer and the molded product for the surface light emitter of the present embodiment is not particularly limited, and a conventionally known multilayer molding method can be applied.
For example, in addition to the two-color molding method in injection molding and the method using a multi-layer T die, a film and a sheet are prepared in advance, and a thermal fusion method is used for this, or bonding is performed through a predetermined adhesive layer. It can be pasted together.

[Surface emitter]
The surface light emitter of the present embodiment includes the above-described molded body for the surface light emitter and a light source disposed so as to face at least one side end surface of the molded body for the surface light emitter.
When light is incident from the side end face of the surface light emitter molded body from the light source, light is emitted from the front side of the surface light emitter molded body, and light is emitted over the entire surface.
For example, an LED or the like can be applied as the light source.

Hereinafter, specific examples will be described in detail with reference to comparative examples.
The measurement methods and evaluation methods applied in the examples and comparative examples described below are shown below and the raw materials used in the examples and comparative examples.

[(A) Measurement and evaluation method]
(1) Styrene content The styrene content was measured using an ultraviolet spectrophotometer (device name: UV-2450; Shimadzu Corporation).

(2) Total light transmittance, haze (cloudiness value)
A flat plate having a thickness of 2 mm, a length of 5 cm, and a width of 4 cm is produced using an injection molding machine (Nissei Resin Industry Co., Ltd., FE120), and a haze meter (1001DP) manufactured by Nippon Denshoku Co., Ltd. is used according to JIS K7105 The total light transmittance and haze (cloudiness value) were measured.
When the total light transmittance was 80% or more and the haze value was 5 to 20%, it was judged to be practically good.

(3) Surface Luminescence The green LED light is irradiated from the lateral end surface (in the direction parallel to the surface) of the flat plate used in the measurement of the total light transmittance in (2), and the color and the light emission area of the light emission state are as follows. It was evaluated as follows.
<Color>
A surface that emits vivid green light: ○
Light emission but faint: △
No light emission or very light emission: ×
<Light emitting area>
Depending on the light emitting distance in the vertical direction, the entire surface emits light uniformly: ○
There is a difference in the brightness of the light on the side opposite to the side irradiated with the LED: △
The surface on the other end side where the LED is irradiated does not emit light: ×

(4) Thickness of phase of polymer block mainly composed of vinyl aromatic hydrocarbon A flat plate having a thickness of 2 mm, a length of 5 cm, and a width of 4 cm was prepared using an injection molding machine (FE120 manufactured by Nissei Resin Co., Ltd.). .
This flat plate was stained by an osmic acid staining method, and an ultrathin section of about 8000 angstroms was cut out using an ultramicrotome UCT (manufactured by Leica), and then a transmission electron microscope (manufactured by JEOL Ltd., JEM-1230). Was used to observe the dispersion in the injection direction (MD) and the direction perpendicular to the injection (TD), and the thickness of the polymer block mainly composed of vinyl aromatic hydrocarbons (phase not dyed black) was measured.
The above observation was performed at a magnification of 20,000 times, and in the photograph of 22 cm × 18 cm, the polymer block mainly composed of vinyl aromatic hydrocarbons with a thickness exceeding 0.2 μm did not exist in part. Was evaluated as x when a polymer block phase mainly composed of vinyl aromatic hydrocarbon having a thickness exceeding 0.2 μm was observed.

[(B) Used material]
(1) Block copolymer (a-1)
Using an autoclave equipped with a stirrer, 0.080 parts by mass of n-butyllithium was added to a cyclohexane solution containing 20 parts by mass of styrene as the (first stage) under a nitrogen gas atmosphere and polymerized at 80 ° C. for 20 minutes.
Next, as a (second stage), a cyclohexane solution containing 0 part by mass of styrene and 60 parts by mass of 1,3-butadiene was continuously added for 60 minutes to polymerize at 80 ° C.
Next, as a (third stage), a cyclohexane solution containing 20 parts by mass of styrene was continuously added for 25 minutes and polymerized at 80 ° C., and then held at 80 ° C. for 10 minutes.
Thereafter, the polymerization was stopped by adding methanol to the polymerization vessel at a 0.9-fold molar ratio with respect to n-butyllithium, and 2- [1- (2-hydroxy-3,5-di-t-pentylphenyl) was used as a stabilizer. ) Ethyl] -4,6-di-t-pentylphenyl acrylate is added in an amount of 0.5 parts by mass with respect to 100 parts by mass of the block copolymer, and then the solvent is removed to obtain the block copolymer (a-1). Obtained.
The block copolymer (a-1) produced as described above is polymer block A in which styrene / 1,3-butadiene = 100/0 mass ratio, styrene / 1,3-butadiene = 0/100 mass. It is an ABA type block polymer composed of a polymer block B having a ratio of styrene / 1,3-butadiene = 100/0 mass ratio.
Table 1 below shows the raw material ratio and the styrene content in the first to third stages of the block copolymer (a-1).

(2) Block copolymer (a-2, b-1, b-2)
Styrene and 1,3-butadiene to be added in the above (first stage), (second stage), and (third stage) by applying the same method as the production process of the block copolymer (a-1) described above. The block copolymer (a-2, b-1, b-2) was produced by changing the addition amount of n and the addition amount of n-butyllithium.
The raw material ratios and styrene contents in the first to third stages of the block copolymer (a-2, b-1, b-2) are shown in Tables 1 and 2 below.

(3) Polystyrene Polystyrene: HF77 (manufactured by PS Japan, MI = 7.7 g / 10 min) was used as (c-1).

[Examples 1-6], [Comparative Examples 1-8]
Pellets were produced with the formulation shown in Table 3 below, using a Ikegai twin screw extruder (PCM30).
Using this pellet, a flat plate having a length of 5 cm, a width of 4 cm, and a thickness of 2 mm was produced at a cylinder temperature of 210 ° C. by an injection molding machine (FE120) manufactured by Nissei Plastic Industry Co., Ltd.
Using this flat plate, as described above, the total light transmittance, haze (cloudiness value), surface luminescence (color, light emission area), and the thickness of the polymer block phase mainly composed of vinyl aromatic are measured. evaluated.
The evaluation results are shown in Table 3 below.

  As shown in Table 3, in each of Examples 1 to 6, the total light transmittance was high, the haze value was low, and excellent surface light emission was obtained.

  The molded product for a surface light emitter formed by molding the resin composition of the present invention has industrial applicability as a display for decoration using a LED light or the like in a store advertisement or a polarizing element.

Claims (6)

It comprises a first polymer block A mainly composed of vinyl aromatic hydrocarbons and a first polymer block B mainly composed of conjugated dienes, and the vinyl aromatic hydrocarbon content is 20 to 40% by mass. A certain block copolymer (a);
It comprises a second polymer block A mainly composed of vinyl aromatic hydrocarbons and a second polymer block B mainly composed of conjugated dienes, and has a vinyl aromatic hydrocarbon content of 70 to 95% by mass.
A block copolymer (b),
The resin composition for surface light emitters whose vinyl aromatic hydrocarbon content in a resin composition is 53 mass% or more. The molded object for surface light emitters which shape | molded the resin composition for surface light emitters of Claim 1 . The surface according to claim 2, wherein the total light transmittance (T%) and haze value (H%) of a flat plate having a thickness of X mm measured in accordance with JIS K7105 satisfy the following formulas (1) and (2). Molded body for luminous body.
98- (98-T) / X> 89 (1)
2.5 <H / X <10 (2) A polymer block phase mainly composed of vinyl aromatic hydrocarbons, and the polymer block phase mainly composed of vinyl aromatic hydrocarbons has a thickness of 0.2 μm or less. The molded object for surface emitting bodies of 2 or 3. The molded object for surface light emitters as described in any one of Claims 2 thru | or 4 which comprises the base material layer of a thermoplastic resin. A molded body for a surface light emitter according to any one of claims 2 to 5,
A light source disposed to face at least one side end surface of the surface light emitter,
Comprising
A surface light emitter that emits light by emitting light from the front side of the surface light emitter molded body when light is incident on a side end surface of the surface light emitter molded body by the light source.