A dental appliance for positioning a patient's teeth includes a removable orthodontic tooth positioning appliance having teeth receiving cavities shaped to directly receive at least some of the patient's teeth and apply a resilient positioning force to the patient's teeth. The appliance includes a hard polymer layer having a hard polymer layer elastic modulus disposed between a first soft polymer layer having a first soft polymer layer elastic modulus and a second soft polymer layer having a second soft polymer layer elastic modulus. The hard polymer layer elastic modulus is greater than each of the first soft polymer layer elastic modulus and the second soft polymer layer elastic modulus. At least one of the first soft polymer layer and the second soft polymer layer has a flexural modulus of greater than about 35,000 psi.

Multilayer polymer sheets are provided, as well as related methods, systems, and appliances.

Multilayer polymer sheets are provided, as well as related methods, systems, and appliances.

The present disclosure provides a jet-black multilayer coating film having excellent properties in high appearance, water resistance, and humidity resistance and comprising a base coating film and a clear coating film formed by a coating composition containing a plant-derived aliphatic polyester mainly and a method for forming the same. A jet-black multilayer coating film comprising a base coating film layer formed by a base coating composition which contains a polyester polyol (A-1) containing a polyol having three or more functions and lactic acid as a consisting component of 80 mol % or more and having a hydroxyl value of 140 to 240 mgKOH/g wherein 70 mol % or more of the hydroxyl groups are secondary hydroxyl groups, an acrylic resin (A-2) with a hydroxyl value of 30 to 80 mgKOH/g and a glass transition point of 40 to 80° C., and a polyisocyanate (A-3), and a clear coating film layer formed on said base coating film layer by a clear coating composition which contains a polyester polyol (B-1) obtained by polymerization of a raw composition of a polyol having three or more functions, sebacic acid, and a diol and having a hydroxyl value of 140 to 240 mgKOH/g, an acrylic resin (B-2) with a hydroxyl value of 120 to 220 mgKOH/g, and a polyisocyanate (B-3).

Various aqueous top coat compositions are described. The compositions include one or more polyurethane dispersions, silica, crosslinker(s), acrylic polymers, and an optional water soluble polyester. The compositions can be used to form top coats which exhibit good resistance to scratches and solvents, and improved ink retention.

An adhesive for laminated sheets comprising a urethane resin obtainable by mixing an acrylic polyol with an isocyanate compound. The acrylic polyol is obtained by polymerizing a mixture including a first monomer having a hydroxyl group and acrylonitrile. The isocyanate compound includes both an isocyanate compound having no aromatic ring and an isocyanate compound having an aromatic ring. Also cured reaction products of the adhesive and films laminated using the adhesive.

A composite skin material for a vehicle includes a fibrous substrate, a polyurethane resin layer provided on the front side of the fibrous substrate, and a woven fabric adhered to the back side of the fibrous substrate through an adhesive layer comprising a polyurethane resin. Openings penetrating the fibrous substrate from the front of the polyurethane resin layer are provided in the composite skin material, and an opening ratio on the front of the polyurethane resin layer is 1 to 15%. The woven fabric has a warp density of 25 to 50 yarns/25.4 mm and a weft density of 30 to 50 yarns/25.4 mm, and the mass per unit area of the adhesive layer is 15 to 100 g/m.sup.2. The composite skin material has air permeability of 5 to 100 cm.sup.3/cm.sup.2.Math.s, tear strength of 20 to 150N, and tensile strength of 50 N/cm or more.

The present invention provides a laminate material having a polyester film and a web of polyester fibers cohesively bonded directly thereto, such that portions of the fibers are bonded to the polyester film and portions of the fibers are free from the polyester film. The invention may also include a glass reinforced polymer layer formed on the laminated facer where the polymer of the glass reinforced polymer layer is commingled with the nonwoven of the laminated facer. The laminate may further include a second polymer layer having a thickness joined to the fiber layer and/or a layer of hot melt adhesive applied to the polyester fibers. Also presented is a composite material having a polyester film, a layer of polyester fibers bonded to the second polymer layer; a second polymer layer joined to the polyester film; and a glass reinforced polymer layer formed on the laminated facer, where the polymer of the class reinforced polymer layer is commingled with the nonwoven of the laminated facer.

To provide a layered polyester film having excellent mechanical properties, transparency, heat resistance, and gas barrier property. A layered polyester film including a polyester film and a thin film layer, wherein the polyester film is a biaxially oriented polyester film including a dicarboxylic acid component containing mainly a furandicarboxylic acid and a glycol component containing mainly ethylene glycol, the covering layer is formed on at least one surface of the polyester film, and the layered polyester film has a plane orientation coefficient ΔP of not less than 0.100 and not more than 0.200, and a thickness of the layered polyester film is not thinner than 1 μm and not thicker than 300 μm.

A multilayer sheet comprising first and second layers is provided. The first layer consists of a co-polyester. The second layer consists of a thermoplastic polyurethane elastomer having an elongation at break of greater than 200%, a hardness of 60A to 85D, an ultimate tensile strength of greater than about 5000 psi, and a light transmission between 400 nm and 800 nm of greater than about 75%. A mold is provided and the multilayer sheet is thermoformed over the mold to form a plurality of tooth-receiving cavities configured to receive and reposition a patient's teeth from a first arrangement toward a second arrangement. Excess material is trimmed from the thermoformed multilayer sheet to form a multilayer dental aligner.