Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – At least one aryl ring which is part of a fused or bridged...
Reexamination Certificate
2000-07-11
2002-04-30
Nutter, Nathan M. (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
At least one aryl ring which is part of a fused or bridged...
C524S451000, C524S500000, C524S502000, C524S503000, C524S515000, C524S522000, C524S533000, C428S476300
Reexamination Certificate
active
06380296
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to interior materials made of a polyolefin resin. More specifically, the present invention pertains to resin type interior materials (ex. floor material, skirt) which can be substituted for conventional PVC resin type interior materials, have excellent scratch resistance, designing applicability and workability and exhibit excellent bond strength or adherence particularly when an adhesive or wax conventionally used for an interior material is employed.
DESCRIPTION OF THE RELATED ART
PVC resins have come to be used widely because they can be easily molded or formed and have excellent designing applicability, and when used as an interior material such as floor material or skirt, have excellent workability and abrasion resistance.
Reflecting much concern for environmental problems in recent years, however, the use of PVC resins is limited because they emit toxic gases such as hydrogen chloride gas or dioxin upon combustion or a phthalate ester plasticizer contained in them is presumed to adversely affect the human body as an endocrine-disturbing substance in the environment. Under such circumstances, polyolefin type interior materials which contain neither halogen nor plasticizers have been proposed. For example, a longer floor material comprising a polyolefin, an ethylene-vinyl acetate copolymer (EVA), and a modified olefin resin or olefin-acrylic copolymer is described in unexamined published Japanese Patent Application JP-A-11-48416.
Polyolefin resins such as polyethylene and polypropylene are, however, not polar compounds. Even if a resin, such as general-purpose EVA (having a polar group concentration of 50% or less) or EEA (ethylene-ethyl acrylate copolymer), having a polar group is incorporated, sufficient adhesive force is not obtained when an adhesive ordinarily employed for interior materials is used. Owing to the same reason, use of a conventional wax for floor materials does not bring about sufficient adherence in the floor material. Moreover, since the resin has high crystallinity, the workability as an interior material is not good and there remains a problem in resistance against whitening on bending particularly when the interior material is a skirt.
SUMMARY OF THE INVENTION
An object of the present invention is, therefore, to provide a polyolefin type interior material which contains neither a halogen nor a phthalate ester plasticizer, has equivalent properties to the PVC type interior material and in particular, exhibits excellent bonding property when an adhesive conventionally employed for interior materials is used.
Another object of the present invention is to provide a polyolefin type interior material having excellent designing applicability and workability and, moreover, having excellent scratch resistance.
A further object of the present invention is to provide a polyolefin type floor material, particularly, a tile-shaped floor material having, in addition to the above-described properties, excellent abrasion resistance and excellent adherence with a wax.
Still a further object of the present invention is to provide a polyolefin type skirt which has, in addition to the above-described properties, excellent resistance against whitening on bending.
DETAILED DESCRIPTION OF THE INVENTION
It has been found that the above-described objects are attained by a resin type interior material which comprises 10 to 45 parts by weight of an ethylene-vinyl acetate copolymer having a vinyl acetate concentration of at least 50 wt. %, 55 to 90 parts by weight of a poloyolefin resin, and 100 to 700 parts by weight of an inorganic filler, wherein the ethylene-vinyl acetate copolymer has a melt flow rate (which will hereinafter be abbreviated as “MFR”) greater by at least 20 g/10 min than the polyolefin resin.
An interior material composed of, as a basic resin, an ethylene-vinyl acetate copolymer having a vinyl acetate content of 50% or greater and a large MFR and a polyolefin resin having a small MFR at a predetermined ratio is, as is apparent from the test data which will be described later, extremely superior to the conventional polyolefin type interior material in adherence with various adhesives or waxes.
The reasons why the adherence of the resin type interior material of the present invention has markedly improved adherence with an adhesive or wax are as follows:
(1) The above-described ethylene-vinyl acetate copolymer has a vinyl acetate content of 50% or greater, indicating that it contains a polar group at a markedly high concentration.
(2) Since the ethylene-vinyl acetate copolymer has an MFR larger by about at least 20 g/10 min than another resin component, in other words, the MRF of the ethylene-vinyl acetate copolymer having a high polar function is largely different from that of another resin component, it is not completely compatible with the mixture, but, is dispersed in the whole system as fine particles. It scatters in the whole system while having a high polar group concentration.
The ethylene-vinyl acetate copolymer having a high polar function takes the dispersed form because it has low crystallinity and is flexible, as a result, a sheet obtained from it has flexibility.
The ethylene-vinyl acetate copolymer has a vinyl acetate content of 50% or greater, preferably 60 to 80%. At a vinyl acetate content of less than 50%, effects for improving the adherence with an adhesive or wax do not appear because the concentration of a polar group is too low.
The ethylene-vinyl acetate copolymer having a high vinyl acetate content (which may hereinafter be called “polar group content”) has an MFR larger by at least 20 g/10 min, preferably at least 30 g/10 min than another resin components (such as polyolefin resin). When the difference of MRF is smaller than 20 g/10 min, the difference between the ethylene-vinyl acetate copolymer having a high polar group content and another resin in MRF becomes smaller and it becomes difficult to form a fine-particle-dispersed structure, making it impossible to attain good adherence.
Although no particular limitation is imposed on the MRF of the ethylene-vinyl acetate copolymer having a high polar group content insofar as it is greater by at least 20 g/10 min than that of a polyolefin resin, it preferably falls within a range of 40 to 100 g/10 min, with a range of 40 to 80 g/10 min being particularly preferred. The MFR of the polyolefin resin preferably falls within a range of 1 to 20 g/10 min, particularly within a range of 1 to 10 g/10 min. At an MFR of the above-described ethylene-vinyl acetate copolymer not greater than 100 g/10 min, the resin can be crystallized sufficiently, good abrasion resistance can be attained and the stickiness of its molded or formed product can be suppressed to an appropriate degree, whereby performances as an interior material are exhibited favorably.
The “MFR” as used herein has the same meaning as melt flow index as described in JIS K 6900 (Plastics Terms) and it can be measured in accordance with JIS K 7210.
The ethylene-vinyl acetate copolymer having a high polar group content and the polyolefin resin are added in amounts of 10 to 45 parts by weight and 55 to 90 parts by weight, respectively, which can, however, be determined as needed within the above range depending on the application or kind of the interior material. Amounts of the ethylene-vinyl acetate copolymer less than 10 parts by weight cause a shortage in high-concentration polar groups to be dispersed in the whole system, thereby making it difficult to bring about the above-described effects of the present invention. When the amount is greater than 45 parts by weight, on the other hand, a portion of the resin with less crystallinity increases, causing a deterioration in abrasion resistance or causing stickiness of the molded or formed product, thereby damaging the performance of the interior material. Amounts outside the above range are, therefore, not preferred.
Although no particular limitation is imposed on the polyolefin resin to be used in the present invention, examples of the p
Nitto Boseki Co. Ltd.
Nutter Nathan M.
Safran David S.
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