Bio-based binders including carbohydrates and a pre-reacted product of an alcohol or polyol and a monomeric or polymeric polycarboxylic acid
An environmentally friendly, formaldehyde-free, aqueous binder composition that includes a carbohydrate, a crosslinking agent, and a pre-reacted product of an alcohol or polyol and monomeric or polymeric polycarboxylic acid or polyglycerol is provided. The pre-reacted product may include glycerol and esters of citric acid such a monoglyceryl citrate, diglyceryl citrate, and triglyceryl citrate as well as other higher molecular weight citric acid-based esters. The inclusion of the pre-reacted product in the binder composition helps to speed the crosslinking reaction, induces faster water evaporation, decreases the viscosity of the binder, helps to reduce the amount of water needed for application of the binder, decreases tackiness, and helps to achieve a maximum vertical expansion of the insulation pack in the transfer zone. The binder composition may be used in the formation of insulation materials and non-woven chopped strand mats.
1. An aqueous binder composition for use in the formation of fiberglass insulation and non-woven mats, the aqueous binder composition comprising:
at least one carbohydrate having a dextrose equivalent number from 2 to 20;
from 1.0 to 40.0 wt. % of at least one crosslinking agent, based on the weight of the total solids in the binder composition; wherein the crosslinking agent comprises one or more of polycarboxylic acids, salts of polycarboxylic acid, anhydrides, citric acid, salts of citric acid, adipic acid, salts of adipic acid, polyacrylic acid, or salts of polyacrylic acid; and
from 10 to 60 wt. % of a pre-reacted product comprising the reaction product of a polyol with citric acid, based on the weight of the total solids in the binder composition, said polyol comprising one or more of glycerol, polyglycerol, triethanolamine, sorbitol, polyethylene glycol, propylene glycol, and ethylene glycol, and wherein said polyol and said citric acid being present in a molar ratio from about 1.5-3.0 moles polyol: 1 mole citric acid;
wherein the pre-reacted product comprises:
from 5 to 25 wt. % of unreacted polyol, based on the weight of the pre-reacted product; and
less than 5 wt. % unreacted citric acid, based on the weight of the pre-reacted product.
2. The aqueous binder composition of claim 1 , wherein the polyol comprises one or more of glycerol, polyglycerol, triethanolamine, and sorbitol.
3. The aqueous binder composition of claim 1 , wherein the carbohydrate is a water-soluble polysaccharide comprising one or more of pectin, dextrin, maltodextrin, and starch.
4. The aqueous binder composition of claim 1 , wherein the crosslinking agent comprises citric acid, salts of citric acid, and combinations thereof.
5. The aqueous binder composition of claim 1 , wherein the aqueous binder composition further comprises one or more of a coupling agent, a moisture resistant agent, a dust suppression agent, a catalyst, an inorganic acid, an organic acid, an inorganic base, and an organic base.
6. The aqueous binder composition of claim 1 , wherein the binder composition further comprises one or more of corrosion inhibitors, dyes, pigments, fillers, colorants, UV stabilizers, thermal stabilizers, anti-foaming agents, anti-oxidants, emulsifiers, preservatives, biocides, fungicides, lubricants, wetting agents, surfactants, antistatic agents, and water repellent agents.
7. The aqueous binder composition of claim 1 , wherein the binder composition comprises:
from 30.0 to 95.0 wt. % of the carbohydrate, based on the weight of the total solids in the binder composition;
from 1.0 to 40.0 wt. % of the crosslinking agent, based on the weight of the total solids in the binder composition; and
from 5.0 to 50.0 wt. % of the pre-reacted product, based on the weight of the total solids in the binder composition.
8. The aqueous binder composition of claim 1 , wherein the pre-reacted product comprises:
(i) from 5 to 25 wt. % of unreacted glycerol, based on the weight of the pre-reacted product;
(ii) from 10 to 70 wt. % of a mixture of monoglyceryl citrate, diglyceryl citrate, and triglyceryl citrate, based on the weight of the pre-reacted product; and
(iii) less than 5 wt. % unreacted citric acid, based on the weight of the pre-reacted product,
wherein the pre-reacted product has a weight average molecular weight from 1500 to 5000 Daltons.
9. The aqueous binder composition of claim 8 , wherein the pre-reacted product comprises from 12 to 50 wt. % of a mixture of monoglyceryl citrate, diglyceryl citrate, and triglyceryl citrate, based on the weight of the pre-reacted product.