JP3516738B2 - Resin composition - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin composition having a whitening property in which transparency changes reversibly depending on environmental temperature. [0002] Blends of resins having slightly different temperature dependences of the refractive index are known. For example, a blend of a methacrylic or styrene-based impact-resistant resin is usually almost transparent at ordinary temperature. When the temperature reaches 100 ° C. or more, the degree of white turbidity is very small at a temperature difference of 20 to 30 ° C. In addition, in the case of blends other than those described above, the compatibility of the resins is usually poor, and no resin composition capable of obtaining good transparency even when blended has been found. [0003] The present invention relates to a resin composition having a whitening property in which the transparency is reversibly changed depending on the environmental temperature, and more specifically, a resin composition having good transparency at room temperature.
It becomes white and opaque at 0 to 50 ° C, or vice versa at 40 to 50 ° C, but becomes opaque at room temperature.
An object of the present invention is to provide a resin composition whose transparency reversibly changes at a temperature difference of 20 to 30 ° C. Means for Solving the Problems The present inventors have conducted intensive studies on a resin composition having a whitening property by reversibly changing the transparency depending on the environmental temperature. As a result, the present invention has been completed. . That is, the present invention comprises 10 to 90 parts by weight of a thermoplastic resin A and 90 to 10 parts by weight of a crosslinked structure resin B ;
The crosslinked structure resin B is composed of a multilayer structure, and each inner layer is substantially
And the sum of the weights of the inner layers is the cross-linked resin B
30% by weight or more, and the outermost layer has fluidity.
As well as good blending with thermoplastic resin A
It has good compatibility and transparency; the difference (ΔN) between the temperature-dependent gradient of the refractive index of the thermoplastic resin A and the temperature-dependent gradient of the refractive index of at least one inner layer of the crosslinked structure resin B is expressed by the formula (1). The present invention relates to a resin composition characterized by satisfying (1). [0005] (However, NdA ^q and NdA ^p are the refractive indexes of the thermoplastic resin A at q ° C. and p ° C., respectively, and NdX ^q and NdX ^p are the respective refractive indexes of the inner layer X of the crosslinked resin B. The refractive index is shown at q ° C. and p ° C.) The present invention will be described below in detail. In general,
Transparency can be obtained by blending two or more resins. The conditions are as follows. Assuming that there are two types of resins, (1) both resins have different refractive indices but have good compatibility, and both resins are micro-dispersed, or (2) both resins are micro-dispersed. The refractive indices are the same, but they do not melt with each other, one resin becomes a uniform resin layer and is micro-dispersed in the other resin, and in order to obtain better transparency, the outermost layer of the micro-dispersed resin is uniform This is the case where it has good compatibility with the resin layer. In the case of (1), the transparency is maintained even when the temperature changes, but in the case of (2), since the two resins are transparent due to the same refractive index, both resins are transparent. If the temperature dependence of the refractive index differs, whitening will occur due to a change in temperature. However, the difference in the temperature dependence of the refractive index of the resin is small, and a change of 50 ° C. or more generally causes the whitening phenomenon to occur, so that the above condition is satisfied and 20 to 3 is satisfied.
It is very difficult to find a resin having a whitening property at a difference of 0 ° C. The present inventors have paid attention to the above points, and as a result of repeated studies, have found a specific combination of resins that satisfy the above conditions and have a whitening property at a difference of 20 to 30 ° C. In order to achieve the object of the invention, the formula (1)
Was found to be necessary. The value of ΔN is preferably ΔN ≧ 1.
5 × 10 ⁻⁴ / ° C. When ΔN <1 × 10 ⁻⁴ / ° C., the change in transparency is very small at a temperature difference of 20 to 30 ° C., which is not preferable. The difference between the gradients of the refractive indices due to the temperature (Δ
The fact that N) is large means that, for example, a resin having a good transparency at 25 ° C. has a refractive index of both resins blended at 25 ° C., but has a large refractive index at 50 ° C. In contrast, it means that light scattering at the interface between the micro-dispersed particles is increased, resulting in a strong whitening phenomenon. The thermoplastic resin A in the present invention includes:
There is no particular limitation as long as the formula (1) is satisfied.
For example, a block unit composed of an aromatic vinyl monomer unit and / or a methacrylic acid alkyl ester monomer unit and a partially or completely hydrogenated isoprene polymer, butadiene polymer, isoprene-butadiene copolymer, etc. It is preferable that the block copolymer is composed of the following block units. In the resin composition of the present invention, the ratio of the thermoplastic resin A to the crosslinked structure resin B must be 10 to 90 parts by weight and the latter is 90 to 10 parts by weight.
When the proportion of the thermoplastic resin is less than 10 parts by weight, the fluidity of the resin composition is deteriorated, so that the moldability is reduced and the change in transparency is reduced, and when it is more than 90 parts by weight, the transparency is reduced. Change is remarkably reduced, which is not preferable. The crosslinked resin B of the present invention comprises a multilayer structure having two or more layers and is produced by an emulsion polymerization method.
Each of the inner layers is substantially crosslinked, and the sum of the weights of the respective inner layers is 30% by weight or more of the crosslinked resin B.
You. It is evenly dispersed in thermoplastic resin A,
No melt mixing. When the sum of the weights of the respective inner layers is less than 30% by weight, the change in transparency is small. Further, the outermost layer has a fluidity, and has good compatibility in a blend with a thermoplastic resin A. Furthermore, thermoplastic resin A
When blended with thermoplastic resin A alone, the outermost layer of crosslinked structure resin B does not necessarily have to be transparent at room temperature, but good transparency can be obtained over a wide temperature range. Are preferred. The following are specific examples of the crosslinked structure resin B. That is, the inner layer is composed of 70 to 99% by weight of methyl methacrylate units, 1 to 30% by weight of aromatic vinyl monomer units, 0 to 20% by weight of other ethylenically unsaturated monomer units copolymerizable therewith, Multifunctional crosslinkable monomer unit and / or polyfunctional graft monomer unit 0.1 to
5% by weight of a copolymer, and its outer layer is 70 to 100% by weight of methyl methacrylate units and 0 to 20% by weight of at least one alkyl acrylate unit having 1 to 8 carbon atoms in the alkyl group. And 0 to 30% by weight of other ethylenically unsaturated monomer units copolymerizable therewith, having an intrinsic viscosity of 0.10 to 0.50 dl / g measured in chloroform at 20 ° C. It is preferably a certain copolymer. The method of blending the resin composition of the present invention is generally a method of melting and mixing in an extruder in pelletizing, sheeting, film forming, etc., but is not particularly limited. Further, an ultraviolet absorber, a lubricant, a dye, and the like which are generally used for the resin composition of the present invention can be added as required. Injection molded articles, sheets and films obtained from the resin composition of the present invention have a very remarkable change in transparency at a temperature difference of 20 to 30 ° C., and can be developed for the intended use. It is. The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the present invention.
In addition,% and part in each Example represent% by weight and part by weight, respectively. Each physical property was determined by the following method. (1) Intrinsic viscosity: Dissolve a certain concentration of acrylic resin in chloroform, and at 20 ° C, use an automatic viscometer (fica, France)
Manufactured by the company). (2) Particle size: measured with an electron microscope. (3) Total light transmittance / haze: ASTM-D1003
(4 mm) (4) Refractive index: Digital precision refractometer KPR-20 (manufactured by Calnew Optical Co., Ltd.) The thermoplastic resin A used in this example (hereinafter, the thermoplastic resin may be abbreviated as resin), And the crosslinked structure resin B was produced by the following method. In the resin production examples, / indicates a copolymer composition and-indicates a block polymer composition. Production of Resin (A-1) 500 parts of cyclohexane and 14 parts of S-butyllithium were charged into a pressure-resistant reaction vessel, heated to 50 ° C., and 50 parts of styrene were continuously dropped, and then 300 parts of isoprene were continuously added. And then continuously charged with 50 parts of styrene and polymerized for 10 hours. The reaction system is then replaced with hydrogen,
Add diatomaceous earth-supported nickel catalyst 8 times and add 15kg / c
The reaction was carried out at 150 ° C. for 10 hours under a hydrogen pressure of m ² . The reaction product was diluted with cyclohexane, the catalyst was separated by filtration, and the filtrate was concentrated and dried under reduced pressure to obtain a resin (A-1). NMR
As a result, it was confirmed that the copolymer was a styrene-hydrogenated isoprene-styrene ternary block copolymer.
5%. The hydrogenation rate based on the iodine value was 99%. Further, the refractive index (Nd) of the resin (A-1) at 20 ° C.
Is 1.500, and the temperature-dependent coefficient of refractive index (ΔNd)
Was -2.93 × 10 ⁻⁴ / ° C. Production of Resin (A-2) A styrene content of 5 was prepared in the same manner as in the resin (A-1).
A styrene-hydrogenated isoprene / butadiene (60% / 40%)-styrene ternary block copolymer having a hydrogenation rate of 97% based on iodine value of 0% was obtained. The refractive index (Nd) at 20 ° C. of the resin (A-2) was 1.530, and the temperature dependence coefficient (ΔNd) of the refractive index was −2.32 × 10 ⁻⁴ / ° C. Production of Resin (A-3) Styrene / methyl methacrylate having a styrene / methyl methacrylate content of 15% / 15% and a hydrogenation rate of 93% based on iodine value was prepared in the same manner as in the resin (A-1). -A hydrogenated isoprene-styrene / methyl methacrylate terpolymer was obtained. The refractive index (Nd) of the resin (A-3) at 20 ° C. was 1.487, and the temperature dependence coefficient (ΔNd) of the refractive index was -2.60 × 10 ⁻⁴ / ° C. Preparation of Resin (A-4) A reaction vessel equipped with a reflux condenser was charged with 100 parts of ion-exchanged water containing a suspending and dispersing agent, and then 85 parts of methyl methacrylate, 15 parts of methyl acrylate, and 0 parts of lauroyl peroxide were added. A mixture of 0.5 part of n-octyl mercaptan and 0.7 part of n-octyl mercaptan was charged, and the mixture was polymerized with stirring in a nitrogen atmosphere at 80 ° C. for 2 hours and then at 95 ° C. for 1 hour to give an intrinsic viscosity of 0.5.
31 dl / g of resin beads were obtained. 30 parts of the obtained resin beads and 70 parts of the resin (A-1) were uniformly melt-mixed to obtain a resin (A-4). The refractive index (Nd) at 20 ° C. of the resin (A-4) was 1.496, and the temperature dependence coefficient (ΔNd) of the refractive index was −2.28 × 10 ⁻⁴ / ° C. Production of Resin (A-5) A reaction vessel equipped with a reflux condenser was charged with 100 parts of ion-exchanged water containing a suspending and dispersing agent, and then 95 parts of methyl methacrylate, 5 parts of methyl acrylate and 0.5 part of lauroyl peroxide were added. 4 parts and a mixture of 0.2 parts of n-octyl mercaptan were charged, and stirred at 80 ° C. under nitrogen atmosphere at 80 ° C. for 2 hours.
Polymerization for 1 hour at 95 ° C. for 1 hour and an intrinsic viscosity of 0.5
4 dl / g resin (A-5) beads were obtained. Resin (A-
5) The refractive index (Nd) at 20 ° C. is 1.490;
The temperature dependence coefficient (ΔNd) of the refractive index is −0.79 × 10 ⁻⁴
/ ° C. Production of Crosslinked Structure Resin (B-1) Ion-exchanged water 200 was placed in a reaction vessel equipped with a reflux condenser.
And 1 part of sodium dioctylsulfosuccinate. The mixture was heated to 70 ° C. while stirring under a nitrogen atmosphere, and then 60 parts of methyl methacrylate, 10 parts of styrene, 1 part of allyl methacrylate and 1 part of a 1% aqueous solution of potassium persulfate were added. The mixture was charged and reacted for 60 minutes to complete the polymerization to form an inner layer. Then, after charging 0.5 part of a 1% aqueous solution of potassium persulfate, 25 parts of methyl methacrylate, 5 parts of methyl acrylate, n-
A monomer mixture consisting of 0.24 parts of octyl mercaptan was continuously added dropwise over 30 minutes, and then maintained for 60 minutes to complete the polymerization to form an outer layer.
A μm double-layer resin latex was obtained. The intrinsic viscosity of the resin obtained by polymerizing only the outer layer under the same conditions is 0.28 dl
/ G. The refractive index of the inner layer at 20 ° C. (Nd)
Is 1.500, and the temperature-dependent coefficient of refractive index (ΔNd)
Was −0.81 × 10 ⁻⁴ / ° C. The resulting latex was added to a 3% aqueous solution of magnesium sulfate, salted out and coagulated, washed with water and dried to obtain a crosslinked resin (B-1). Production of Crosslinked Structure Resin (B-2) Ion-exchanged water 200 was placed in a reaction vessel equipped with a reflux condenser.
And 1 part of sodium dioctylsulfosuccinate, and the mixture was heated to 70 ° C. while stirring under a nitrogen atmosphere. The mixture was charged and reacted for 60 minutes to polymerize, thereby obtaining a crosslinked resin latex having a particle diameter of 0.16 μm. The refractive index (Nd) at 20 ° C. of the crosslinked resin layer is 1.500, and the temperature dependence coefficient (ΔNd) of the refractive index is −0.81 × 10 ⁻⁴ / ° C.
Met. The obtained latex was added to a 3% aqueous solution of magnesium sulfate, salted out and coagulated, washed with water and dried to obtain a crosslinked resin (B-2). Preparation of Crosslinked Structure Resin (B-3) In the same manner as in the crosslinked structure resin (B-1), 30 parts of methyl methacrylate, 20 parts of styrene, and 1.0 part of 1,3-butylene glycol dimethacrylate were added. Polymerized inner layer, 45 parts of methyl methacrylate, 5 parts of ethyl acrylate
And a two-layer resin latex having a particle diameter of 0.12 μm, comprising an outer layer obtained by polymerizing 0.3 parts of n-octyl mercaptan. The intrinsic viscosity of the resin obtained by polymerizing only the outer layer under the same conditions was 0.34 dl / g. The refractive index (Nd) of the inner layer at 20 ° C. is 1.530, and the temperature-dependent coefficient of refractive index (ΔNd) is −0.95 × 10 ⁻⁴ /.
° C. The resulting latex was added to a 3% aqueous solution of magnesium sulfate, salted out and coagulated, washed with water and dried to obtain a crosslinked resin (B-3). Preparation of Crosslinked Structure Resin (B-4) In the same manner as for crosslinked structure resin (B-1), 58 parts of methyl methacrylate, 2 parts of methyl acrylate and 0.5 part of allyl methacrylate were polymerized. A two-layer resin latex having a particle diameter of 0.23 μm, comprising an inner layer and an outer layer obtained by polymerizing 39 parts of methyl methacrylate, 1 part of methyl acrylate, and 0.3 part of n-octylmercaptan, was obtained. The intrinsic viscosity of the resin obtained by polymerizing only the outer layer under the same conditions was 0.29 dl / g. The refractive index (Nd) at 20 ° C. of the inner layer was 1.489, and the temperature dependence coefficient (ΔNd) of the refractive index was −0.76 × 10 ⁻⁴ / ° C. The obtained latex was freeze-coagulated at −20 ° C., melted in warm water at 80 ° C., washed with water and dried to obtain a crosslinked resin (B-4). Production of Crosslinked Structure Resin (B-5) An inner layer obtained by polymerizing 50 parts of butyl acrylate, 10 parts of styrene and 1 part of allyl methacrylate by a method similar to that of the crosslinked structure resin (B-1). Methyl methacrylate 39
Part, 1 part of methyl acrylate, and an outer layer formed by polymerizing 0.3 part of n-octyl mercaptan.
A μm double-layered resin latex was obtained. The intrinsic viscosity of the resin obtained by polymerizing only the outer layer under the same conditions is 0.48 dl.
/ G. The refractive index of the inner layer at 20 ° C. (Nd)
Is 1.487, and the temperature-dependent coefficient of refractive index (ΔNd)
Was -1.42 × 10 ⁻⁴ / ° C. The obtained latex was freeze-coagulated at −20 ° C., then thawed in warm water at 80 ° C., washed with water and dried to obtain a crosslinked resin (B-5). Examples 1 to 7 and Comparative Examples 1 to 2 Resin A and crosslinked resin B were mixed in a mixer with the composition shown in Table 1 and fed into a closed kneader under a nitrogen atmosphere.
The mixture was melt-mixed at 230 ° C. and 100 rpm for 5 minutes.
A 2 mm flat plate was formed from the obtained mixture by hot press molding, and the optical properties were measured. The results are as shown in Table 1. [Table 1] The resin composition having a whitening property according to the temperature of the present invention has a very remarkable change in transparency at a temperature difference of 20 to 30 ° C. By taking advantage of this effect, injection molded articles and sheets are utilized. It can also be applied as a film to carports, shopping arcades and eaves, exteriors such as arcades, greenhouses, and sun visors for cars.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) C08L 51/00

Claims (1)

(57) [Claims 1] A thermoplastic resin A is composed of 10 to 90 parts by weight and a crosslinked structure resin B is composed of 90 to 10 parts by weight ; the crosslinked structure resin B is composed of a multilayer structure, and each inner layer has Substantive
And the sum of the weights of the inner layers is the cross-linked resin B
30% by weight or more, and the outermost layer has fluidity.
As well as good blending with thermoplastic resin A
It has good compatibility and transparency; the difference (ΔN) between the temperature-dependent gradient of the refractive index of the thermoplastic resin A and the temperature-dependent gradient of the refractive index of at least one inner layer of the crosslinked structure resin B is expressed by the formula (1). A) a resin composition satisfying the above condition. (Equation 1) (However, NdA ^q and NdA ^p are the refractive indexes of the thermoplastic resin A at q ° C. and p ° C., respectively.
dX ^q and NdX ^p represent the refractive index of the inner layer X of the crosslinked resin B at q ° C. and p ° C., respectively. )