Vinyl articles having improved solar reflectance - Patents.com

Abstract

The vinyl article includes a vinyl substrate and an infrared reflective film disposed on the vinyl substrate. The infrared reflective film has a reflectance of greater than 30% for wavelengths between 800 and 1000 nm and a transmittance of greater than 60% for wavelengths between 400 and 700 nm. A process for producing the vinyl article is also disclosed.

Description

[Technical field]

[0001] The present invention relates to vinyl articles having improved solar reflectance. [Background technology]

[0002] Vinyl articles, especially vinyl substrates exposed to sunlight, such as vinyl siding and trim, often suffer from defects due to solar radiation. For example, a common defect in vinyl siding is called "oil canning." Oil canning manifests as the appearance of surface bulges, waves, and ripples in vinyl planks during use. Oil canning is caused by temperature increases due to solar radiation.

[0003] One attempt to minimize oil canning is to add white pigments to vinyl planks because they can scatter solar radiation and reduce the heat generated. Such techniques are disclosed, for example, in U.S. Patent Application Publication No. 2012 / 0052317. However, the addition of white pigments can have some drawbacks. One problem is that white pigments cannot scatter sunlight sufficiently in high temperature areas. Many white pigments designed to scatter visible light do not scatter near infrared (NIR) effectively. Furthermore, white pigments cannot be used in darker shade vinyl siding.

[0004] Other attempts to minimize oil canning include attempts to improve the heat distortion temperature and / or reduce the coefficient of thermal expansion of vinyl siding.

[0005] It would therefore be desirable to develop vinyl articles with improved resistance to oil canning without the drawbacks of existing remediations. Summary of the Invention

[0006] One aspect of the present invention relates to a vinyl article comprising a vinyl substrate and an infrared reflective film disposed on the vinyl substrate, the infrared reflective film having a reflectance of more than 30% for wavelengths of 800 to 1000 nm and a transmittance of more than 60% for wavelengths of 400 to 700 nm.

[0007] A further aspect of the invention relates to a process for making a vinyl article comprising providing a vinyl substrate and laminating an infrared reflective film onto the vinyl substrate, the infrared reflective film having a reflectance of greater than 30% for wavelengths between 800 and 1000 nm and a transmittance of greater than 60% for wavelengths between 400 and 700 nm. [Brief description of the drawings]

[0008] [Figure 1] 1 is an AFM image of an infrared reflective film according to one embodiment of the present invention. [Diagram 2] 2 is a specular reflectance spectrum of an infrared reflective film according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] The inventors have discovered that defects in vinyl articles caused by solar radiation can be significantly reduced by adding to the vinyl article a visually transparent film that is reflective in the near infrared (IR) range (i.e., IR reflective). Since 50% of the solar energy is in the wavelengths between 750 nm and 1200 nm, the IR reflective film can reflect sunlight and reduce the surface temperature of the vinyl article. This improvement can be achieved for vinyl article articles of all colors without significantly changing the appearance of the underlying vinyl substrate and without requiring modification of the composition of the underlying vinyl substrate.

[0010] As used herein, the term "polymer" refers to a polymeric compound prepared by polymerizing monomers, whether of the same or different types. The general term "polymer" includes the terms "homopolymer," "copolymer," and "resin." As used herein, the term "polymerized units derived from" refers to a polymer molecule synthesized according to a polymerization technique in which the product polymer contains "polymerized units derived from" the constituent monomers that are the starting materials for the polymerization reaction. As used herein, the term "(meth)acrylate" refers to either acrylate or methacrylate or a combination thereof, and the term "(meth)acrylic" refers to either acrylic or methacrylic or a combination thereof. As used herein, the term "substituted" refers to having at least one attached chemical group, such as an alkyl group, an alkenyl group, a vinyl group, a hydroxyl group, a carboxylic acid group, other functional groups, and combinations thereof.

[0011] As used herein, the term "weight average molecular weight" or "Mw" refers to the weight average molecular weight of a polymer as measured by gel permeation chromatography ("GPC") on an acrylic acid polymer against polystyrene calibration standards according to ASTM D5296-11(2011) and using tetrahydrofuran ("THF") as the mobile phase and diluent. As used herein, the term "weight of a polymer" refers to the dry weight of the polymer.

[0012] As used herein, when it is stated that a "polymeric composition contains little or no of a particular substance," it means that the polymeric composition does not contain any of that substance, or, if any of that substance is present in the composition, the amount of that substance is 1% by weight or less, based on the weight of the polymeric composition. Among embodiments described herein as having "little or no" of a particular substance, embodiments are contemplated in which none of the particular substance is present.

[0013] Disclosed herein is a vinyl article comprising a vinyl substrate and an infrared reflective film disposed on the vinyl substrate.

[0014] Preferably, the vinyl substrate comprises a polyvinyl chloride (PVC) substrate. However, the composition of the vinyl substrate is not limited and may comprise any vinyl polymer known in the art. Preferably, the vinyl substrate is a plank of vinyl siding, architectural trim, or foamed vinyl substrate (e.g., PVC foam board used in decking, fascia pergolas, and other exterior building products).

[0015] The infrared reflective film has a reflectance of more than 30% for wavelengths between 800 and 1000 nm, including wavelengths in the near infrared region. Preferably, the infrared reflective film has a reflectance of more than 40% for wavelengths between 800 and 1000 nm. More preferably, the infrared reflective film has a reflectance of more than 50% for wavelengths between 800 and 1000 nm. Even more preferably, the infrared reflective film has a reflectance of more than 60% for wavelengths between 800 and 1000 nm. The reflectance / transmittance is measured using a PerkinElmer Lambda 950 UV-Vis-NIR spectrometer and a 60 mm Integrated Sphere Accessory with a resolution of 2 nm (slit width) and a data interval of 2 nm. The detector response time was 0.2 seconds and 8° of reflection / transmission data was collected.

[0016] In addition to reflectance in the near infrared region, the infrared reflective film has a transmittance of more than 60% for wavelengths of 400 to 700 nm, i.e., the visible region. Preferably, the infrared reflective film has a transmittance of more than 70% for wavelengths of 400 to 700 nm. More preferably, the infrared reflective film has a transmittance of more than 80% for wavelengths of 400 to 700 nm.

[0017] Preferably, the thickness of the infrared reflective film is in the range of 5 micrometers to 100 micrometers. For example, the thickness of the infrared reflective film may be at least 10 micrometers, at least 20 micrometers, at least 30 micrometers, or at least 40 micrometers, and the thickness of the infrared reflective film may be less than 100 micrometers, less than 90 micrometers, less than 80 micrometers, less than 70 micrometers, or less than 60 micrometers.

[0018] Preferably, the infrared reflective film comprises a first polymeric material having a refractive index n1 and a second refractive index n2. The refractive index contrast n1 / n2 is preferably greater than 1.04. More preferably, the refractive index contrast is greater than 1.05. Even more preferably, the refractive index contrast is greater than 1.06.

[0019] Preferably, the first polymeric material has a refractive index n1 greater than 1.5. Examples of the first polymeric material include, but are not limited to, polycarbonate, polyethylene naphthalate, polystyrene, polyethylene terephthalate, polysulfone, polyamide, cyclic polyolefin, polyvinyl chloride, polyvinylidene chloride. Preferably, the first polymeric material comprises polycarbonate, which has a refractive index of 1.58.

[0020] Preferably, the second polymeric material has a refractive index n2 of less than 1.5. Examples of the second polymeric material include, but are not limited to, poly(methyl methacrylate), polyvinylidene fluoride, and polyethylene oxide. Preferably, the second polymeric material comprises poly(methyl methacrylate), which has a refractive index of about 1.49.

[0021] Preferably, the first polymeric material of the infrared reflective film comprises polycarbonate and the second polymeric material comprises poly(methyl methacrylate), such that the infrared reflective film has a refractive index contrast (n1 / n2) of about 1.06.

[0022] Preferably, the infrared reflective film comprises a plurality of alternating layers of a first polymeric material and a second polymeric material. Each of the alternating layers can have an average thickness in the range of 100 to 250 nm, preferably 110 to 225 nm, more preferably 120 to 200 nm. As defined herein, the "average thickness" of a layer means that the arithmetic average of all layers in the infrared reflective film is between the recited range. Preferably, each layer in the infrared reflective film has a thickness variation of less than 50% of the average thickness of all layers.

[0023] The infrared reflective film preferably comprises 50 to 400 alternating layers of the first and second polymeric materials, ie, 25 to 200 layers of each material.

[0024] Another aspect of the invention relates to a process for producing a vinyl article. The process includes providing a vinyl substrate and laminating an infrared reflective film, as described above, onto the vinyl substrate. As used herein, the term "providing a vinyl substrate" means that the vinyl substrate is produced or obtained for use in the process, but does not require that the vinyl substrate be produced by the present method. For example, the vinyl substrate can be produced and transported to a location where the infrared reflective film is laminated onto the vinyl substrate. The term "lamination" means that the infrared reflective film is bonded to the vinyl substrate, for example, using an adhesive.

[0025] In the process of the present invention, the infrared reflective film can be manufactured, for example, by extrusion. A first polymeric material and a second polymeric material can be co-extruded to form an infrared reflective film consisting of alternating layers. The extruded film can be cooled on a chill roll to form the infrared reflective film.

[0026] To laminate the infrared reflective film to the vinyl substrate, the infrared reflective film can be adhered to the surface of the vinyl substrate using a suitable adhesive, such as, for example, a water-based acrylic adhesive. EXAMPLES

[0027] Preparation and measurement of infrared reflective film Calibre 200-14NA natural resin (MFI=14 dg / min, 300° C. / 1.2 kg) was obtained from Trinseo, LLC. Plexiglas V045-100 (MFI=2.3 dg / min, 230° C. / 3.8 kg) was received from Arkema Inc. Polycarbonate (PC) and poly(methyl methacrylate) (PMMA) resins were dried overnight in ovens at 120° C. and 80° C. to reduce the moisture content before processing.

[0028] A coextrusion line was utilized for the microlayer extrusion testing, consisting of two single screw extruders with a diameter of 31.75 mm (1.25 in), 24:1 L / D. The extruders fed individual gear pumps to ensure uniform flow of the polymer melt to the feedblock and die. Precision feedrings were used to produce layered coextrusion structures with 100 or 200 layers. They were combined with a skin layer (50% by volume) and extruded through an 8 inch wide film die at 20 lb / hr into films with thicknesses ranging from 12 to 50 micrometers. Extruder and die temperatures were set at 243°C. The extruded films were cooled on a chill roll set at 104°C.

[0029] Cross-sectional multilayer film samples were prepared by punching specimens from the samples and mounting them in a vice holder. The samples were ground flat in a cryo-grinding mill at approximately -80°C. The samples were then polished by cryo-microtome at -80°C. The block faces were inspected. Peak force tapping AFM images were obtained on a Bruker Icon using a Nanoscope V controller (software v8.15). The cantilever used was a NanoWorld Arrow NCR with settings outlined in AL-2016-005591. All images were taken at 1024 lines of resolution and generated with SPIP version 6.4.2. software. A quadratic average plane fit with zero-order LMS was used and the average was set to zero. Layer measurements were made in ImageJ. The average thickness of the PC layers was 163 nm and the average thickness of the PMMA layers was 152 nm. An AFM image of an exemplary film is shown in Figure 1.

[0030] IR reflectance was measured using a PerkinElmer Lambda 950 UV-Vis-NIR spectrometer and a 60 mm Integrating Sphere Accessory with a resolution (slit width) of 2 nm and a data interval of 2 nm. The detector response time was 0.2 seconds. 8° reflectance data was collected. Figure 2 shows the specular reflectance spectrum of an infrared reflective film according to one embodiment of the present invention.

[0031] The total solar reflectance of the films was measured using a Solar Spectrum Reflectometer SSR-ER (Devices & Services Company). The comparative example is a 127 micrometer (5 mil) thick transparent impact resistant polycarbonate film (85585K102 from McMaster-Carr Co.). The total solar reflectance results are summarized in Table 1.

[0032] [Table 1]

[0033] As can be seen in Table 1, the infrared reflective film of the present invention has significant solar reflectance and is transparent in the visible range.

[0034] Thermal heating reduction measurement Four different vinyl siding products were obtained from Lowe's. They were from Georgia-Pacific's Compass Series and came in a variety of dark colors including Heartstone Brown (Example 1), Redwood (Example 2), Pewter (Example 3), and Coastal Blue (Example 4). Two samples of each color were adhered to a 1-inch thick polystyrene foam substrate to essentially block all heat transfer underneath the samples.

[0035] Two samples of each product were adhered side-by-side to a substrate. One sample was a comparative example and an infrared reflective film according to the invention was adhered to the front of the other sample with an adhesive that was a water-based acrylic adhesive. The adhesive appeared clear at the applied thickness.

[0036] On a sunny day with occasional clouds, the sample panels were exposed to sunlight in horizontal and vertical orientations. Testing was performed between 11:00 AM and 2:00 PM, with the ambient temperature at approximately 30° C. Each exposure condition was continued for approximately 45 minutes to reach steady state. The horizontal orientation mimicked direct sunlight exposure, which is the worst case scenario for solar heating. The vertical orientation mimicked grazing incidence, or average exposure conditions. The sample surface temperatures were measured by a FLIR TG167 thermal imaging thermometer. The results are shown in Table 2 below.

[0037] [Table 2]

[0038] As seen in Table 2, the samples with the infrared reflective film of the present invention have a lower temperature than the control sample under the same sun exposure conditions. The temperature of all samples after sun exposure is less than 63°C. The temperature difference between the examples and the comparative examples depends on the color (NIR spectrum included) of the vinyl product. The product "Redwood" showed a maximum temperature difference of 8°C under direct sun exposure. The reduced temperature provided by the infrared reflective film of the present invention is expected to prevent oil canning of PVC vinyl siding.

Claims

1. A vinyl article comprising: a vinyl substrate; an infrared reflective film disposed on the vinyl substrate, the infrared reflective film having a reflectance of greater than 30% for wavelengths of 800 to 1000 nm and a transmittance of greater than 60% for wavelengths of 400 to 700 nm.

2. 10. The vinyl article of claim 1, wherein the vinyl substrate comprises polyvinyl chloride (PVC) resin.

3. 10. The vinyl article of claim 1, wherein the infrared reflective film comprises a first polymeric material having a refractive index n1 and a second polymeric material having a refractive index n2, wherein n1 / n2 is greater than 1.

04.

4. 4. The vinyl article of claim 3, wherein said infrared reflective film comprises multiple alternating layers of said first polymeric material and said second polymeric material.

5. 5. The vinyl article of claim 4, wherein each of the plurality of alternating layers of the first polymeric material and the second polymeric material has an average thickness in the range of 100 to 250 nm.

6. 4. The vinyl article of claim 3, wherein the first polymeric material is selected from the group consisting of polycarbonate, polyethylene naphthalate, polystyrene, polyethylene terephthalate, polysulfone, polyamide, cyclic polyolefin, polyvinyl chloride, polyvinylidene chloride, and the second polymeric material is selected from the group consisting of poly(methyl methacrylate), polyvinylidene fluoride, and polyethylene oxide.

7. 4. The vinyl article of claim 3, wherein said first polymeric material comprises polycarbonate and said second polymeric material comprises poly(methyl methacrylate).

8. 5. The vinyl article of claim 4, wherein said infrared reflective film comprises 50 to 400 alternating layers of said first polymeric material and said second polymeric material.

9. 10. The vinyl article of claim 1, wherein the infrared reflective film has a reflectance of greater than 40% for wavelengths between 800 and 1000 nm and a transmittance of greater than 70% for wavelengths between 400 and 700 nm.

10. 10. The vinyl article of claim 1, wherein the vinyl article comprises vinyl siding, architectural trim, or foam vinyl substrate plank.

11. 1. A process for manufacturing a vinyl article, comprising: providing a vinyl substrate; and laminating an infrared reflective film onto the vinyl substrate; The process wherein the infrared reflective film has a reflectance of greater than 30% for wavelengths between 800 and 1000 nm and a transmittance of greater than 60% for wavelengths between 400 and 700 nm.

12. 12. The process of claim 11, wherein the infrared reflective film is formed by co-extruding a first polymeric material and a second polymeric material to form 50 to 400 alternating layers and casting the formed layers onto a chill roll to obtain the infrared reflective film.

13. 13. The process of claim 12, wherein the first polymeric material has a refractive index n1 and the second polymeric material has a refractive index n2, and n1 / n2 is greater than 1.

04.

14. 13. The process of claim 12, wherein the first polymeric material is selected from the group consisting of polycarbonate, polyethylene naphthalate, polystyrene, polyethylene terephthalate, polysulfone, polyamide, cyclic polyolefin, polyvinyl chloride, polyvinylidene chloride, and the second polymeric material is selected from the group consisting of poly(methyl methacrylate), polyvinylidene fluoride, and polyethylene oxide.

15. The process of claim 12, wherein each of the layers of the first and second polymeric materials has an average thickness in the range of 100 to 250 nm.

16. 12. The process of claim 11, wherein the infrared reflective film has a reflectance of greater than 40% for wavelengths between 800 and 1000 nm and a transmittance of greater than 70% for wavelengths between 400 and 700 nm.

17. The process of claim 11 , wherein the vinyl article comprises a polyvinyl chloride resin.

18. 12. The process of claim 11, wherein the vinyl article comprises vinyl siding, architectural trim, or foam vinyl substrate planks.

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