JP3974189B2 - UV resistant elastomer monofilament - Google Patents

Description

織布試験結果
本発明の延伸された織られた保持材は、第一の方向と、第一の方向に垂直の第二の方向とに交差したストランドを具える構造を有する織布である。この第一の方向のストランドは、コポリエーテルエステル、ポリウレタン、およびポリエステルアミドよりなる群から選択された鞘／芯構造の延伸された熱可塑性エラストマーモノフィラメントを含有し、該鞘は芯のエラストマーの融点より少なくとも２０℃低い融点を有するエラストマーである。前述の第二の方向のストランドは、第一の方向のストランドと同じ、または、以下の具体例のように非エラストマーの天然または合成糸を含有するストランドでもよい。このような糸としては、綿、ポリエステル、ナイロン、レーヨン、アクリル、モダクリリック、およびオレフィン糸が挙げられるが、これに限定されるわけではない。布保持材は、ここで参照され本明細書の一部を構成する米国特許第４，４６９，７３９号に記載されているように製造され、Dymetrol（登録商標）brandの織られた、加熱シールされたスプリング布（E. I. du Pont de Nemours and Company,ウィルミントン、デラウエア州）として入手可能である。サンプルのDymetrol（登録商標）布を、ＳＡＥＪ１８に従ってWeatherometer（登録商標）内で紫外光に曝し、物理的にインストロン引張試験器内で試験した。布は１４横糸の同時押出された芯鞘エラストマーモノフィラメントウィーブ、ポリエステル縦糸の朱子織、および全てのサンプルはモノフィラメントの方向に引っ張られた。
各場合において、朱子織布の主にポリエステル面および主にモノフィラメント面の両方は、各面が光源に面するように試験にかけられた。これらの面は、以下の試験結果の報告された表２に、それぞれ「白」面および「黒」面と表す。

布サンプル幅：２．５４ｃｍ（正確に１４ストランドモノフィラメント）
ＳＡＥＪ１８８５に準じたＵＶ露光試験
インストロン：ゲージ長１０．１６ｃｍ
クロスヘッド速度：２５．４ｃｍ／分
試験条件：２３℃、５０％ＲＨ
試験：露光試験当たり３サンプルの得られた結果の平均
モノフィラメント組成：芯Hytrel（登録商標）７２４６、鞘Hytrel（登録商標）４０５６、７５体積％の芯と２５体積％の鞘とからなるモノフィラメント
得られた結果より、モノフィラメントの鞘および芯成分に２．５％の炭素添加を有する布は、その布の強度および結合性が、Weatherometer（登録商標）で少なくとも４５１．２ＫＪ／ｍ²のＵＶ露光レベルに対して保たれることがわかる。例えば、朱子織布サンプルの主にモノフィラメントの面が直接にWeatherometer（登録商標）のキセノン光源に曝された「黒」サンプルを考えると、応力−ひずみ曲線の下の面積であり、したがって破断負荷および伸びの組み合わせを表す靭性は２５，１００％に改善されたことがわかる。
外部自動車Weatherometer（登録商標）試験結果
ＵＶ試験をWeatherometer（登録商標）で実施した。この耐候試験器でサンプルを試験手段ＳＡＥＪ１９６０に従って断続的に湿らせる標準外部自動車サイクルにかけた。引張結果を以下の表３に示す。

BACKGROUND OF THE INVENTION The present invention relates to a method for improving the resistance of elastomeric polyester monofilaments, in particular co-extruded bicomponent monofilaments, to degradation that occurs upon exposure to ultraviolet (UV) light. More particularly, the present invention relates to a UV resistant elastomeric monofilament having a sheath and a core, each of which has a UV protection amount of carbon in the range of about 1.8 wt% to 3.0 wt%. Including.
U.S. Pat. No. 4,469,739 describes a stretched and woven furniture carrier consisting of an elastomeric monofilament part and a natural or synthetic yarn part. The elastomer is woven in a first direction and yarns are woven in a second direction perpendicular to the first direction, and the resulting woven fabric is then heat set. In one embodiment, the thermoplastic elastomer filament is a coextruded bicomponent core-sheath monofilament, and the elastomer comprising the sheath has a melting point that is at least 20 ° C. lower than the core elastomer. To date, the use of such woven fabrics, for example as chair retainers, has been limited to applications that are not exposed to ultraviolet light, such as coating the fabric with other layers of material and direct or indirect exposure to ultraviolet light. Limited to applications that prevent contact with the fabric. Ultraviolet light has been found to cause a substantial decline in the physical properties of the woven fabric, particularly the elastomeric monofilament component of the fabric.
SUMMARY OF THE INVENTION The present invention is a two-component elastomeric polyester monofilament comprising a sheath and a core that is resistant to degradation by direct or indirect exposure to ultraviolet light, which provides a UV protective amount of carbon to the sheath and core elastomeric material. The discovery is that it is essentially improved by inclusion. Thus, in one embodiment, the present invention is a method for improving the UV resistance of a bicomponent elastomeric monofilament having a core and a sheath by including a UV protective amount of carbon in the core and the sheath.
In another aspect, the present invention is an improved two-component elastomer monofilament having a core consisting essentially of a first polyester elastomer and a sheath consisting essentially of a second polyester elastomer, The sheath elastomer has a melting point that is at least 20 ° C. lower than the first elastomer. The improvement of the present invention is that the first elastomer and the second elastomer described above contain about 1.8 wt.% To about 3.0 wt. Including an amount in the range of%. In a preferred embodiment, first a concentrate containing 75% by weight of elastomer and 25% by weight of carbon is prepared, then the corresponding base at a ratio of 10% by weight of concentrate to 90% by weight of base elastomer. Carbon is incorporated into each elastomer composition by uniformly blending the elastomer with a carbon / elastomer concentrate. The concentration of each carbon in the resulting core elastomer component and sheath elastomer component is in the above range, and for most preferred results, the carbon concentration is about 2.5% by weight.
In yet another aspect, the present invention is an improved stretched and woven retainer, such as a furniture retainer, having a strand intersecting a first direction and a second direction perpendicular to the first direction. is doing. The strand in this first direction contains a stretched thermoplastic elastomer monofilament of a sheath / core structure selected from the group consisting of copolyetheresters, polyurethanes, and polyesteramides, where the sheath is of core elastomer. An elastomer having a melting point at least 20 ° C. below the melting point. The aforementioned second direction strands contain non-elastomeric natural or synthetic yarns. This improvement of the present invention incorporates a UV protective amount of carbon, such as generally in the range of about 1.8 wt.% To about 3.0 wt.%, Preferably 2.5 wt. Including that.
When carbon is incorporated into both the core and sheath as described, the resulting elastomeric monofilament has an essentially improved resistance to degradation by UV light than when carbon is incorporated alone or not at all. Have.
DETAILED DESCRIPTION OF THE INVENTION The thermoplastic elastomer used in the core-sheath monofilament of the present invention is a stretchable copolyetherester elastomer, polyurethane elastomer, or polyesteramide elastomer, and the melting point of the sheath component is substantially higher than the melting point of the core component. Low, ie at least about 20 ° C. below the melting point of the core elastomer. The preferred thermoplastic elastomer used in the present invention is one of U.S. Pat. Nos. 3,651,014, 3,763,109, 3,766,146, and 4,136,715. A copolyetherester elastomer as described above. The teachings of these US patents are hereby incorporated by reference herein. Such copolyetherester polymers consist essentially of a number of repeating in-line long and short chain ester units linked end to end through ester bonds, the chemical structure of which is well known to those skilled in the art. It has been.
A preferred embodiment of the present invention is that the monofilament sheath is Hytrel® 4056 polyetherester block copolymer and the monofilament core is Hytrel® 7246 polyetherester block copolymer (EI du Pont de Nemours and Company, Wilmington, commercially available from Delaware). Monofilaments are produced by coextrusion of the core and sheath from a thermoplastic material melted through a die by conventional methods known to those skilled in the art as described in US Pat. No. 5,313,909. The While the exact ratio of core to sheath containing elastomer can vary over a wide range, usually monofilaments are composed of about 75% core and about 25% sheath.
The carbon used in the present invention can be any commercially available carbon black, such as Vulcan® 9A32 or Elftex 12 (available commercially from Cabot Corporation) having a “fine” to “intermediate” particle size. “Fine” means that the particle size of carbon black is generally in the range of about 19 nm, and “intermediate” particle size means that the carbon particles are from about “fine” to about 37-41 nm in size. It means that it is in the range. Carbon with finer particle size tends to protect at a higher level from UV degradation. However, finer particles are more difficult to disperse in the polymer and also tend to absorb moisture more quickly than intermediate or coarse carbon particles. Regardless of the particle size, a grade of carbon black having the lowest possible moisture absorption rate is preferred.
For best results, it is important that the carbon black is uniformly distributed within the sheath and core polymer components. Such uniform distribution is achieved by first producing a carbon / elastomer “concentrate” containing 25 wt% carbon and 75 wt% of each base elastomer. The carbon component is well mixed and dispersed in the corresponding molten base elastomer in an instrument designed for this purpose, such as a Farrell Continuous Mixer or a Banbury mixer. Subsequently, the concentrate is cut into pellets using either a melt cutter or a strand cutter. In a preferred embodiment of the invention, drying may be performed after blending, but before blending with the corresponding base elastomer, the carbon-containing concentrate is in the range of 0.005 wt% to 0.02 wt%. Pre-dry to low moisture level. It has been found that low moisture content increases the processability of base polymers containing carbon. The pre-dried carbon-containing concentrate in the form of pellets and the respective base polymer of the pellet-like core and sheath are subsequently premixed, generally with the carbon-containing concentrate in the base polymer pellet mixture as a whole. Make it evenly distributed. Each base polymer pellet mixture is then extruded with a single or twin screw extruder. Within this extruder, the melting and even mixing of the components is melted while metering the melt into a die system where the sheath and core components are formed in a heated die designed for this purpose. It happens in the state. The molten strand exits the die and is cooled and then post-stretched in the machine direction to impart strength to the monofilament. The drawn monofilament is then wound on a spool.
Test Monofilament samples prepared as described above, i.e. monofilament sheath is Hytrel <(R)> 4056 polyetherester block copolymer and monofilament core is Hytrel <(R)> 7246 polyetherester block copolymer. One monofilament sample was placed in a Xenon light source standard Weatherometer® (ie, “indoor test cycle”) and exposed to UV light at levels of 200 and 400 KJ / m ² . This cycle was performed according to SAEJ 1885. Control samples for each production run were retained and protected from exposure to any ultraviolet light. The following table lists these control samples as “0” KJ / m ² exposure samples.
After exposure to ultraviolet light, there were three samples for each run, all samples were tensile tested in an Instron tensile tester. Samples were 10 inches (25.4 cm) gauge length, crosshead speed was set to 10 inches / minute (25.4 cm / minute), and all samples were preconditioned at 23 ° C. and 40% RH for 24 hours did. Table 1 below shows the reported tensile properties for each sample.
In visual inspection of the samples before the test, all the samples exposed to ultraviolet light, except for the sample containing 2.5% carbon in the core and sheath, were cracked and cracked on the surface. The sample containing 2.5% carbon in the core and sheath had a very bright and smooth surface appearance similar to the control sample. The sample containing 2.5% by weight of carbon in the present invention shows almost no difference in breaking load, tensile strength, and particularly elongation at break, compared to the non-exposed (0 KJ / m ² ) sample.

Results of woven fabric test The stretched woven holding material of the present invention has a structure having a structure including strands intersecting a first direction and a second direction perpendicular to the first direction. It is cloth. The strand in the first direction contains a stretched thermoplastic elastomer monofilament of a sheath / core structure selected from the group consisting of copolyetheresters, polyurethanes, and polyesteramides, the sheath being from the melting point of the core elastomer. An elastomer having a melting point that is at least 20 ° C. lower. The aforementioned second direction strands may be the same as the first direction strands or may contain non-elastomeric natural or synthetic yarns as in the following examples. Such yarns include but are not limited to cotton, polyester, nylon, rayon, acrylic, modacrylic, and olefin yarns. The fabric retainer is manufactured as described in U.S. Pat. No. 4,469,739, which is hereby incorporated by reference, and is a woven, heat seal of Dymetrol® brand. Spring fabric (EI du Pont de Nemours and Company, Wilmington, Delaware). Sample Dymetrol® fabric was exposed to ultraviolet light in a Weatherometer® according to SAEJ18 and physically tested in an Instron tensile tester. The fabric was 14 weft co-extruded core-sheath elastomer monofilament weave, polyester warp satin weave, and all samples were pulled in the direction of the monofilament.
In each case, both the predominantly polyester side and the predominantly monofilament side of the satin woven fabric were tested so that each side faces the light source. These planes are represented as “white” plane and “black” plane in Table 2 where the following test results are reported.

Fabric sample width: 2.54 cm (exactly 14 strand monofilament)
Instron UV exposure test according to SAEJ1885: Gauge length 10.16 cm
Crosshead speed: 25.4 cm / min Test conditions: 23 ° C., 50% RH
Test: Average monofilament composition of the results obtained for 3 samples per exposure test: core Hytrel® 7246, sheath Hytrel® 4056, a monofilament consisting of 75% by volume core and 25% by volume sheath is obtained. The results show that a fabric with 2.5% carbon addition in the monofilament sheath and core components has a fabric strength and bond strength of at least 451.2 KJ / m ² UV exposure level with a Weatherometer®. It can be seen that this is maintained. For example, considering a “black” sample in which the monofilament face of the satin weave fabric sample was directly exposed to a Weatherometer® xenon light source, it is the area under the stress-strain curve, and therefore the breaking load and It can be seen that the toughness representing the combination of elongation was improved to 25,100%.
External car Weatherometer (registered trademark) test results The UV test was conducted with a Weatherometer (registered trademark). In this weathering tester, the sample was subjected to a standard external vehicle cycle where the sample was intermittently wetted according to test means SAEJ1960. The tensile results are shown in Table 3 below.

Claims (7)

A method for improving the UV resistance of a bicomponent elastomeric monofilament having a core and a sheath, wherein the core consists essentially of a first elastomer, and the sheath has a melting point that is at least 20 ° C. lower than the first elastomer Consisting essentially of a second elastomer, wherein the core elastomer and the sheath elastomer are selected from the group consisting of copolyetheresters, polyurethanes, and polyesteramides, and the core and sheath have 1.8 carbon as a UV protective agent. A method for improving UV resistance, comprising a step of mixing in the range of wt% to 3.0 wt%. First forming a carbon / elastomer concentrate of each component containing 75% by weight of each of the elastomers and 25% by weight of carbon;
Drying the concentrate to a low moisture level in the range of 0.005 wt% to 0.02 wt% moisture;
Then uniformly blending the carbon / elastomer concentrate obtained in the corresponding base elastomer in a proportion of 10% by weight of concentrate and 90% by weight of base elastomer;
The carbon is mixed with each of the core elastomer component and the sheath elastomer component, and the carbon concentration in the obtained core elastomer component and the sheath elastomer component is 1.8 wt% to 3.0 wt%. 2. A method according to claim 1, characterized in that it is in the range of% by weight. The carbon / elastomer concentrate is first uniformly blended with each corresponding base polymer, and the resulting base polymer / concentrate blend is then mixed with a moisture level of the concentrate of 0.005 wt% to 0.02 wt%. The method according to claim 2, wherein the drying is performed until the range is reached. A bicomponent elastomer monofilament with improved UV resistance having a core consisting essentially of a first elastomer and a sheath consisting essentially of a second elastomer,
The second elastomer has a melting point that is at least 20 ° C. lower than the first elastomer;
The core and the sheath elastomer are selected from the group consisting of copolyetheresters, polyurethanes, and polyesteramides;
The improvement is made by mixing in a range of 1.8 wt% 3.0 wt% carbon as UV protective agent in the first elastomer and the second elastomer,
Two-component elastomer monofilament characterized by The monofilament according to claim 4, wherein the carbon has a particle size having a size in a range of 19 nm to 45 nm. A stretched woven fabric with improved UV resistance having a structure comprising strands intersecting a first direction and a second direction perpendicular to the first direction,
The strand in the first direction contains a stretched thermoplastic elastomer monofilament with a sheath / core structure selected from the group consisting of copolyetheresters, polyurethanes, and polyesteramides, the sheath comprising an elastomer that constitutes the core An elastomer having a melting point that is at least 20 ° C. lower than the melting point of, and the strands in the second direction contain non-elastomeric natural or synthetic yarns, the improvement being the first elastomer and the second elastomer And carbon as a UV protective agent mixed in the range of 1.8 wt% to 3.0 wt%,
A stretched woven fabric with improved UV resistance , characterized by: The strand in the second direction contains a stretched thermoplastic elastomer monofilament of a sheath / core structure selected from the group consisting of copolyetheresters, polyurethanes, and polyesteramides, the sheath constituting the core An elastomer having a melting point that is at least 20 ° C. lower than the melting point of the elastomer, and the carbon is uniformly distributed in the sheath and core at a concentration in the range of 1.8 wt% to 3.0 wt%. A stretched woven fabric having improved UV resistance according to claim 6.