JP2013254105A - Light diffusion heat shrinkable tube and straight-tube led light - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light diffusion heat shrinkable tube which has excellent light diffusion properties and exhibits excellent light source concealment properties, and can turn an LED point light source to a soft surface light source image; and a straight-tube LED light having the light diffusion heat shrinkable tube.SOLUTION: A light diffusion heat shrinkable tube contains a polyester resin having an intrinsic viscosity of 0.8-1.4 dl/g, organic resin particles and titanium oxide particles, and a weight ratio between the organic resin particles and the titanium oxide particles is 7:3-3:7.

Description

The present invention relates to a light diffusing heat-shrinkable tube that is excellent in light diffusibility and exhibits good light source concealability, and that can make a point light source of an LED a soft surface light source image. The present invention also relates to a straight tube type LED light having the light diffusion heat shrinkable tube.

In recent years, LEDs (light emitting diodes) have been attracting attention for illumination. Since the LED is power-saving and has a long life, the burden on the environment is small compared to conventional fluorescent lamps and the like. In particular, future demand for straight tube LED lights is expected.

However, since the LED is a point light source and is a brilliant and exciting light, there are problems such as a large burden on the eyes. For this reason, various attempts have been made to obtain a soft surface light source image such as a conventional fluorescent lamp even in a transparent tube including an LED light source, particularly a transparent tube including a plurality of LED light sources.
For example, attempts have been made to knead a light diffusing agent into a transparent tube or a lighting cover for covering the transparent tube, or to apply a light diffusing agent to the surface. Furthermore, an example in which a sheet or film having a light diffusion function is wound around a transparent tube has been reported.
Patent Document 1 discloses a light transmission diffuser filter for an illumination lamp in which a light diffusing material such as quartz glass fine particles and titanium dioxide, silica, calcium and the like is uniformly dispersed in a translucent resin.

However, in these methods, particularly when the distance from the LED light source to the transparent tube is short, the point light source may still be observed or it may become a glaring and exciting light, which is similar to a conventional fluorescent lamp. It was difficult to obtain a soft surface light source image.

JP 2010-192415 A

It is an object of the present invention to provide a light diffusing heat-shrinkable tube that is excellent in light diffusibility and exhibits a good light source concealing property and can make a point light source of an LED a soft surface light source image. Another object of the present invention is to provide a straight tube type LED light having the light diffusion heat shrinkable tube.

The present invention contains a polyester resin having an intrinsic viscosity of 0.8 to 1.4 dl / g, organic resin particles, and titanium oxide particles, and the weight ratio of the organic resin particles to the titanium oxide particles is 7: 3. A light diffusing heat-shrinkable tube that is ~ 3: 7.
The present invention is described in detail below.

The inventor is excellent in light diffusibility and good by adding organic resin particles and titanium oxide particles at a predetermined weight ratio to a polyester resin having an intrinsic viscosity of 0.8 to 1.4 dl / g. It was found that a light diffusion heat-shrinkable tube that shows a good light source concealing property and can make the LED point light source a soft surface light source image is obtained. Such a light diffusing heat-shrinkable tube is excellent in heat-shrinkability and has sufficient strength, and therefore is suitably used as an illumination cover for covering a transparent tube containing an LED light source.

The light diffusion heat-shrinkable tube of the present invention contains a polyester resin having an intrinsic viscosity of 0.8 to 1.4 dl / g. By setting the intrinsic viscosity of the polyester resin within this range, it is possible to obtain a light diffusion heat shrinkable tube having excellent heat shrinkability and sufficient strength.
If the intrinsic viscosity is less than 0.8 dl / g, the strength of the light diffusing heat-shrinkable tube will decrease, and if the transparent tube containing the LED light source is damaged due to an accident such as dropping, the fragments will scatter greatly. If it exceeds 1.4 dl / g, the polyester resin has a high melt viscosity and is difficult to extrude. The preferable lower limit of the intrinsic viscosity is 1.0 dl / g, and the preferable upper limit is 1.2 dl / g. In addition, the said intrinsic viscosity means the value measured in orthochlorophenol at 35 degreeC.

Examples of a method for setting the intrinsic viscosity of the polyester resin in the above range include, for example, a method of adjusting the composition of the dicarboxylic acid component and the diol component constituting the polyester resin, and the content of other copolymerization components in the polyester resin. Examples thereof include a method of adjusting, a method of adjusting the number average molecular weight of the polyester resin, and the like.

Examples of the dicarboxylic acid include terephthalic acid, isophthalic acid, 2-chloroterephthalic acid, 2,5-dichloroterephthalic acid, 2-methylterephthalic acid, 4,4-stilbene dicarboxylic acid, 4,4-biphenyldicarboxylic acid, Orthophthalic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, bisbenzoic acid, bis (p-carboxyphenyl) methane, anthracene dicarboxylic acid, 4,4-diphenyl ether dicarboxylic acid, 4,4-diphenoxy Ethanedicarboxylic acid, 5-Na sulfoisophthalic acid, ethylene-bis-p-benzoic acid, adipic acid, sebacic acid, azelaic acid, dodecanedioic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, etc. Can be mentioned. These dicarboxylic acids may be used alone or in combination of two or more.

Examples of the diol include diethylene glycol, ethylene glycol, 1,2-propylene glycol, 1,3-propanediol, 2,2-dimethyl-1,3-propanediol, trans- or -2,2,4,4. -Tetramethyl-1,3-cyclobutanediol, 1,4-butanediol, neopentyl glycol, 1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, 1,3-cyclohexanedi Examples include methanol, decamethylene glycol, and cyclohexanediol. These diols may be used alone or in combination of two or more.

The polyester resin having an intrinsic viscosity of 0.8 to 1.4 dl / g includes, among other things, a component derived from terephthalic acid as the dicarboxylic acid component and a component derived from ethylene glycol as the diol component. Those that do are preferred. By using such a polyester resin, heat resistance can be imparted to the light diffusion heat shrinkable tube.
The polyester resin containing a component derived from terephthalic acid as the dicarboxylic acid component and a component derived from ethylene glycol as the diol component may contain other copolymer components, The content of other copolymerization components in the resin is preferably 10 mol% or less. When the content exceeds 10 mol%, the strength of the light diffusion heat-shrinkable tube decreases, and if the transparent tube containing the LED light source is damaged due to an accident such as dropping, the fragments are likely to be scattered greatly. Sometimes.

As the polyester resin having an intrinsic viscosity of 0.8 to 1.4 dl / g, a polyester resin having the above-described composition may be used alone, or two or more polyester-based resins having the above-described composition are used in combination. May be.

The minimum with a preferable number average molecular weight of the polyester-type resin whose said intrinsic viscosity is 0.8-1.4 dl / g is 30000, and a preferable upper limit is 55000. When the number average molecular weight is less than 30000, the strength of the light diffusion heat-shrinkable tube may be reduced, and when it exceeds 55000, extrusion molding may be difficult. In addition, the said number average molecular weight means the value measured by gel permeation chromatography (GPC).

The light diffusion heat shrinkable tube of the present invention contains organic resin particles and titanium oxide particles. By using organic resin particles and titanium oxide particles in combination, the light diffusion heat-shrinkable tube is provided with excellent light diffusibility and good light source concealment, and the LED point light source is made into a soft surface light source image. Can do.
On the other hand, when organic resin particles are not used, the light diffusibility is likely to be lowered, and when titanium oxide particles are not used, the LED light source cannot be sufficiently concealed.

Examples of the organic resin particles include styrene resin particles, acrylic resin particles, and silicone resin particles. Among these, acrylic resin particles and silicone resin particles are preferable, and silicone resin particles are more preferable.

Examples of the styrenic resin constituting the styrenic resin particles include polystyrene, a copolymer with a monomer copolymerizable with styrene, and the like. Examples of the copolymer of the monomer copolymerizable with styrene include a styrene- (meth) acrylic acid copolymer. Here, “(meth) acrylic acid” represents methacrylic acid or acrylic acid.

Examples of the acrylic resin constituting the acrylic resin particles include poly (meth) acrylic acid, a copolymer of (meth) acrylic acid and (meth) acrylic acid ester, and the like.
The (meth) acrylic acid ester is not particularly limited, and examples thereof include methyl (meth) acrylate and ethyl (meth) acrylate.
The acrylic resin constituting the acrylic resin particles may or may not have a crosslinked or partially crosslinked structure.

The silicone resin constituting the silicone resin particles is not particularly limited as long as it is a silicone resin such as organopolysiloxane having a siloxane bond as a skeleton.

The organic resin particles preferably do not melt at the melting temperature of the polyester resin and are insoluble in the solvent, and the shape is preferably spherical rather than indefinite.

The preferable lower limit of the average particle diameter of the organic resin particles is 0.5 μm, and the preferable upper limit is 20.0 μm. By setting the average particle diameter of the organic resin particles within this range, good dispersibility without secondary aggregation can be obtained.
When the average particle diameter is less than 0.5 μm, the effect of adding organic resin particles may not be sufficiently obtained. When the average particle diameter exceeds 20.0 μm, the total light transmittance of the light diffusion heat-shrinkable tube decreases. However, sufficient brightness (illuminance) may not be obtained. The average particle size can be measured by a laser diffraction particle size distribution analyzer (for example, Microtrac MT3000II manufactured by Nikkiso Co., Ltd.).

The organic resin particles preferably have a low refractive index. The preferable lower limit of the refractive index of the organic resin particles is 1.41, and the preferable upper limit is 1.57. By setting the refractive index of the organic resin particles within this range, the difference in refractive index from the polyester resin is increased, and the light diffusibility of the light diffusion heat-shrinkable tube can be improved. A more preferable upper limit of the refractive index is 1.51.

The preferable lower limit of the content of the organic resin particles in the light diffusion heat-shrinkable tube of the present invention is 0.1% by weight, and the preferable upper limit is 2.5% by weight. If the content is less than 0.1% by weight, the light diffusibility of the light diffusing heat-shrinkable tube may be reduced, or the LED light source may be observed as a point light source, exceeding 2.5% by weight. And the total light transmittance of a light-diffusion heat-shrinkable tube may fall, and sufficient brightness (illuminance) may not be obtained. The more preferable lower limit of the content is 0.5% by weight, and the more preferable upper limit is 2.0% by weight.

As said titanium oxide particle, what is generally used as a light-diffusion agent or a white pigment can be used. The crystal type of the titanium oxide particles is not particularly limited, and examples thereof include anatase type and rutile type. Of these, the rutile type is preferable.

The preferable lower limit of the average particle diameter of the titanium oxide particles is 0.2 μm, and the preferable upper limit is 20.0 μm. If the average particle diameter is less than 0.2 μm, the titanium oxide particles may exhibit photocatalytic action, which may lead to a decrease in strength of the light diffusion heat-shrinkable tube, and if it exceeds 20.0 μm, the light diffusion heat The total light transmittance of the shrinkable tube may be reduced, and sufficient brightness (illuminance) may not be obtained, and pinholes may be generated during stretching in the manufacturing process of the light diffusion heat-shrinkable tube. A more preferable upper limit of the average particle diameter is 10 μm, and a more preferable upper limit is 5 μm. The average particle size can be measured by a laser diffraction particle size distribution analyzer (for example, Microtrac MT3000II manufactured by Nikkiso Co., Ltd.).

The preferable lower limit of the refractive index of the titanium oxide particles is 2.40, and the preferable upper limit is 2.80. By setting the refractive index of the titanium oxide particles within this range, good light diffusibility and light source concealment can be obtained.

The preferable lower limit of the content of the titanium oxide particles in the light diffusion heat-shrinkable tube of the present invention is 0.1% by weight, and the preferable upper limit is 2.5% by weight. When the content is less than 0.1% by weight, the light diffusibility of the light diffusing heat-shrinkable tube may be lowered or the LED light source may not be sufficiently concealed, and the content exceeds 2.5% by weight. And the total light transmittance of a light-diffusion heat-shrinkable tube may fall, and sufficient brightness (illuminance) may not be obtained. The more preferable lower limit of the content is 0.5% by weight, and the more preferable upper limit is 2.0% by weight.

The weight ratio of the organic resin particles to the titanium oxide particles in the light diffusion heat-shrinkable tube of the present invention is 7: 3 to 3: 7. By setting such a weight ratio, the light diffusibility of the light diffusing heat-shrinkable tube can be further improved and good light source concealing property can be maintained, and the LED point light source can be a soft surface light source image. The weight ratio is preferably 6: 4 to 4: 6.

The light diffusing heat-shrinkable tube of the present invention includes a heat stabilizer, an antistatic agent, an antiblocking agent, a lubricant, a quencher, a nucleating agent, a flame retardant, etc. within the range that does not impair the essence of the present invention. Known additives may be added.

The structure of the light diffusion heat shrinkable tube of the present invention may be a single layer or a multilayer.

The preferable lower limit of the tube thickness of the light diffusion heat-shrinkable tube of the present invention is 60 μm, and the preferable upper limit is 300 μm. By setting the tube thickness within this range, an appropriate elasticity and strength can be imparted to the light diffusion heat-shrinkable tube, and the ease of handling is improved.
If the tube thickness is less than 60 μm, the light diffusibility and the light source concealing property of the light diffusion heat shrinkable tube may be lowered, the strength is lowered, and the transparent tube containing the LED light source is inadvertently dropped. If it breaks due to the above accident, the fragments are likely to scatter greatly, and if it exceeds 300 μm, the light diffusion heat-shrinkable tube becomes too thick and is bright enough to cover the transparent tube containing the LED light source ( (Illuminance) may not be obtained. The preferable lower limit of the tube thickness is 90 μm, and the preferable upper limit is 250 μm.

The light diffusion heat-shrinkable tube of the present invention is excellent in light diffusibility. “Excellent light diffusibility” means that the total light transmittance is large and the parallel light transmittance is small, and that the illuminance maintenance ratio as described later is large.
The light diffusion heat-shrinkable tube of the present invention preferably has a total light transmittance of 20% or more and a parallel light transmittance of 5% or less. If the total light transmittance is less than 20%, sufficient brightness (illuminance) may not be obtained when a transparent tube containing an LED light source is covered with a light diffusion heat shrinkable tube. If the parallel light transmittance exceeds 5%, the LED point light source may not be a soft surface light source image.

In the light diffusing heat-shrinkable tube of the present invention, it is preferable that the illuminance maintenance ratio at a position horizontally moved by X mm from directly below the LED light source is 10% or more in the range of X ≦ 200. If the illuminance maintenance rate is less than 10%, the uniformity of brightness (illuminance) may not be maintained.
In addition, the said illumination intensity maintenance factor says the value represented by a following formula.
Illuminance maintenance rate (%) = (I _X / I ₀ ) × 100
In the formula, I ₀ represents the illuminance immediately below the LED light source, and I _X represents the illuminance at a position horizontally moved by _X mm from directly below the LED light source.

The light diffusion heat shrinkable tube of the present invention has heat shrinkability.
The heat shrinkage rate of the light diffusion heat shrinkable tube of the present invention is preferably 20 to 40% in the axial direction (MD direction) and 35 to 50% in the radial direction (TD direction). Thereby, for example, a transparent tube containing an LED light source is inserted into the light diffusion heat-shrinkable tube and the light diffusion heat-shrinkable tube is thermally shrunk so that the entire surface of the transparent tube can be easily and beautifully covered. . The thermal shrinkage rate is obtained by biaxial stretching and refers to a value represented by a dimensional change rate when contracted by treatment with boiling water for 30 seconds.

Although it does not specifically limit as a method to manufacture the light-diffusion heat-shrinkable tube of this invention, After mixing polyester-type resin with an intrinsic viscosity of 0.8-1.4 dl / g, an organic resin particle, and a titanium oxide particle, a tube Examples thereof include a method of biaxially stretching a raw tube extruded into a shape.

The use of the light diffusion heat-shrinkable tube of the present invention is not particularly limited, but it is preferably used for coating a transparent tube containing an LED light source, particularly a plurality of transparent tubes.
The light diffusing heat-shrinkable tube of the present invention is excellent in light diffusibility and exhibits good light source concealment, and can make a point light source of an LED into a soft surface light source image. Even in a tube, the entire tube can have uniform brightness (illuminance). Further, the light diffusion heat shrinkable tube of the present invention is excellent in heat shrinkability and has sufficient strength, so that the entire surface of the transparent tube can be covered, and further, the transparent tube is damaged by an accident such as dropping. Even if you do, you can suppress the scattering of debris.
A straight tube type LED light in which the transparent tube containing the LED light source is coated with the light diffusion heat-shrinkable tube of the present invention is also one aspect of the present invention.

According to the present invention, it is possible to provide a light diffusing heat-shrinkable tube that is excellent in light diffusibility and exhibits good light source concealability, and that can make a point light source of an LED into a soft surface light source image. Moreover, according to this invention, the straight tube | pipe type LED light which has this light diffusion heat-shrinkable tube can be provided.

It is a figure which shows the shape of the sample for a measurement used in the measurement of tensile strength. It is a figure which shows typically the evaluation method of an illumination intensity maintenance factor. It is a figure which shows typically the evaluation method of light source concealment property. It is a photograph which shows the case (evaluation (circle)) when the LED light source was favorably concealed in the light source concealment evaluation method. Although it is not observed as a point light source in the light source hiding property evaluation method, it is a photograph showing a case where the hiding of the LED light source is insufficient (evaluation Δ). It is a photograph which shows the case where an LED light source is observed as a point light source in the light source concealment evaluation method (evaluation x).

Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.

Example 1
Polyethylene terephthalate (inherent viscosity 1.10 dl / g) as polyester resin, silicone resin fine particles (average particle size 2 μm, refractive index 1.41), titanium oxide particles (average particle size 0.5 μm, refractive index) as organic resin particles 2.71), and the resin composition obtained by mixing them in the proportions shown in Table 1 was introduced into an extruder adjusted to a temperature on the inlet side of 260 ° C. and a temperature near the tip adjusted to 280 ° C. Extruded from a die into a circular tube. Next, a light diffusion heat-shrinkable tube having a folding diameter of 55.0 mm (inner diameter φ34.8) and a tube thickness of 100 μm is obtained by biaxial stretching at 95 ° C. at a stretching ratio of 3.0 times in length and 2.5 times in width. Obtained.

(Examples 2 to 10 and Comparative Examples 1 to 6)
A light-diffusing heat-shrinkable tube was obtained in the same manner as in Example 1 except that the polyester resin, organic resin particles, and titanium oxide particles were changed to the types and ratios shown in Table 1.

(Evaluation)
The following evaluation was performed about the light-diffusion heat-shrinkable tube obtained by the Example and the comparative example. The results are shown in Table 2.

(1) Heat shrinkage rate The obtained light diffusion heat shrinkable tube is treated with boiling water for 30 seconds to shrink, and the dimensional change rate in the axial direction (MD direction) and radial direction (TD direction) before and after shrinkage is obtained. The heat shrinkage rate was used. The thermal shrinkage rate was determined using the following formula.
Thermal shrinkage rate (%) = {(size before shrinkage−size after shrinkage) / size before shrinkage} × 100

(2) The light-diffusing heat-shrinkable tube cut in the tensile strength axial direction (MD direction) into a film shape into a No. 3 dumbbell shape (the shape shown in FIG. 1, the unit of the numerical value in FIG. 1 is mm) A sample for punching measurement was used. Using a tensile tester (Toyo Seiki Seisakusho, V10-C), the tensile strength (MD direction) was measured at a distance between chucks of 70 mm and a tensile speed of 200 mm / min.

(3) Shrinkage Finish Evaluation A fluorescent tube (length 1198 mm) was inserted into a light diffusion heat shrinkable tube, and the light diffusion heat shrinkable tube was thermally contracted by heating at 200 ° C. × 30 sec to coat the fluorescent tube. The fluorescent tube after coating was visually observed, and the case where wrinkles due to shrinkage spots (unevenness) were observed was evaluated as x, and the case where it was not observed was evaluated as ○.

(4) Total light transmittance and parallel light transmittance About the obtained light diffusion heat-shrinkable tube, using a haze meter (manufactured by Toyo Seiki Seisakusho, direct reading haze meter), the total light transmittance and the diffuse transmittance are measured. did. The parallel light transmittance was determined using the following formula.
Parallel light transmittance (%) = total light transmittance−diffuse transmittance

(5) Illuminance maintenance rate FIG. 2 schematically shows an evaluation method for this evaluation.
As shown in FIG. 2, a light diffusion heat shrinkable tube 1 cut in the axial direction (MD direction) and formed into a film was sandwiched between two glass plates 2 (thickness 5 mm) to form a sample for measurement. The light diffusion heat shrinkable tube 1 in the measurement sample is disposed at a position 15 mm directly below the LED light source 3, and the illuminance meter 4 is disposed at a position 200 mm from the light diffusion heat shrinkable tube 1 in the measurement sample. the illumination I ₀ just below the light source was measured. Next, while moving the illuminance meter horizontally, the illuminance I _X at the position horizontally moved by _X mm from directly below the LED light source is measured, and the illuminance maintenance rate when X = 50, 100, 150, and 200 using the following formula: Asked.
Illuminance maintenance rate (%) = (I _X / I ₀ ) × 100

(6) Light source concealing property FIG. 3 schematically shows an evaluation method for this evaluation.
As shown in FIG. 3, the light diffusion heat shrinkable tube 1 cut in the axial direction (MD direction) and formed into a film was sandwiched between two glass plates 2 (thickness 5 mm) to obtain a sample for measurement. The distance between the LED light source 3 and the light diffusion heat-shrinkable tube 1 in the measurement sample was 15 mm, and the degree of concealment of the LED light source was observed.
A case where the LED light source is well concealed as shown in FIG. 4 is shown as ◯, a case where the LED light source is not sufficiently concealed as shown in FIG. Thus, the case where the LED light source was observed as a point light source was evaluated as x.

According to the present invention, it is possible to provide a light diffusing heat-shrinkable tube that is excellent in light diffusibility and exhibits good light source concealability, and that can make a point light source of an LED into a soft surface light source image. Moreover, according to this invention, the straight tube | pipe type LED light which has this light diffusion heat-shrinkable tube can be provided.

DESCRIPTION OF SYMBOLS 1 Light diffusion heat-shrinkable tube cut into axial direction (MD direction) and made into film shape 2 Glass plate 3 LED light source 4 Illuminance meter

Claims (8)

It contains a polyester resin having an intrinsic viscosity of 0.8 to 1.4 dl / g, organic resin particles, and titanium oxide particles, and the weight ratio of the organic resin particles to the titanium oxide particles is 7: 3 to 3: 7. A light-diffusing heat-shrinkable tube, characterized in that The light-diffusing heat-shrinkable tube according to claim 1, wherein the content of the organic resin particles is 0.1 to 2.5% by weight. The light diffusion heat-shrinkable tube according to claim 1 or 2, wherein the content of titanium oxide particles is 0.1 to 2.5% by weight. 4. The light diffusing heat-shrinkable tube according to claim 1, 2 or 3, wherein the organic resin particles are acrylic resin particles or silicone resin particles. 5. The light diffusing heat-shrinkable tube according to claim 1, wherein the organic resin particles have an average particle size of 0.5 to 20.0 [mu] m. The light diffusion heat-shrinkable tube according to claim 1, 2, 3, 4, or 5, wherein the titanium oxide particles have an average particle diameter of 0.2 to 20.0 µm. 7. The light diffusing heat-shrinkable tube according to claim 1, wherein the total light transmittance is 20% or more and the parallel light transmittance is 5% or less. A straight tube type LED light characterized in that the light diffusion heat-shrinkable tube according to claim 1, 2, 3, 4, 7, or 7 is covered with a transparent tube containing the LED light source.