Translucent white polymer composition and its use in glass laminates and other articles
Provided herein is a translucent white polymer composition suitable for use as a safety glass interlayer. The translucent white polymer composition comprises a pigment and a polymeric resin that comprises an ionomer of an ethylene acid copolymer. Alumina (Al 2 O 3 ) and alumina trihydrate (Al(OH) 3 ; “ATH”) are preferred pigments. The translucent white polymer composition is useful in various molded articles. The translucent white polymer composition is particularly useful as an interlayer in glass laminates, including safety glass laminates and structural glass laminates. Further provided herein are methods of making the translucent white polymer composition, the articles and the glass laminates.
1. A glass laminate comprising an interlayer and at least one glass sheet, said interlayer comprising a film or sheet of a translucent white polymer composition comprising from 1.0 to about 10.0 wt %, based on the total weight of the translucent white polymer composition, of a pigment mixed into a resin, wherein:
the resin is an ethylene acid copolymer or an ionomer of an ethylene acid copolymer;
the pigment consists essentially of alumina trihydrate; said pigment having an index of refraction of about 1.5 to about 2.8; and said pigment consisting essentially of particles having a minimum average size of about 380 nm, a median particle size (d50) of about 1.5 to about 3.0 microns, and an aspect ratio close to 1; and
the film or sheet of the translucent white polymer composition has a transmission of less than 90%, a haze of 75 to 100%, an L* value higher than 80, an a* value that ranges from −0.2 to −1.8, and a b* value that ranges from 0.8 to 4.0.
2. The glass laminate of claim 1 , wherein the film or sheet of the translucent white polymer composition has a transmission of from 56 to 75%, a haze of from 90 to 100%, a clarity of from 10 to 30%, an L* value that ranges from 80 to 90, an a* value that ranges from −0.2 to −1.8, and a b* value that ranges from 1.0 to 4.0.
3. The glass laminate of claim 1 , wherein the film or sheet of the translucent white polymer composition has a transmission of from 80 to 90%, a haze of from 75 to 85%, a clarity of from 70 to 86%, an L* value that ranges from 85 to 96, an a* value that ranges from −0.8 to −1.6, and a b* value that ranges from 0.8 to 2.0.
4. The glass laminate of claim 1 , wherein the alumina trihydrate has a median particle size of from 1.5 to 4.5 microns.
5. The glass laminate of claim 1 , wherein the 90° peel adhesion strength of the film or sheet to the glass sheet is greater than 2.0 N/mm.
6. The glass laminate of claim 1 , wherein the modulus of the translucent white polymer composition is from about 20 to about 60 kpsi.
7. The glass laminate of claim 1 , wherein the strength of the interlayer is about 20 to about 40 MPa.
8. The glass laminate of claim 1 , wherein the elongation at break of the laminate is about 200 to about 400%.
9. The glass laminate of claim 1 , wherein the ethylene acid copolymer comprises copolymerized units of ethylene; about 8 to about 30 wt % copolymerized units of acrylic acid, methacrylic acid, or a combination of acrylic acid and methacrylic acid; and, optionally copolymerized units of one or more additional comonomers selected from the group consisting of derivatives of one or more unsaturated carboxylic acids, said unsaturated carboxylic acids having 2 to 10 carbon atoms, and said derivatives selected from the group consisting of acid anhydrides, amides and esters.
10. The glass laminate of claim 9 , wherein the ethylene acid copolymer is an ionomer in which about 5% to about 90% of carboxylic acids groups are neutralized, based on the total carboxylic acid content of the ethylene acid copolymer.
11. The glass laminate of claim 1 , which is a safety glass laminate.
12. The glass laminate of claim 1 , which is a structural glass laminate.