NL1039737C2

NL1039737C2 - Mehod for the manufacture of a sorbic acid-based polymer network.

Info

Publication number: NL1039737C2
Application number: NL1039737A
Authority: NL
Inventors: Erik Diederik Jurri N Visser; Martinus Adrianus Gertrudus Jansen
Original assignee: Hovis Internat B V
Priority date: 2012-07-17
Filing date: 2012-07-17
Publication date: 2014-01-20
Also published as: WO2014012941A2; WO2014012941A3

Abstract

The present invention relates to a method for the manufacture of a polymer network comprising: a) reacting a glycidylether with one or more compounds comprising a sorbic acid-based moiety and obtaining a product having a predetermined viscosity; and c) polymerizing the product obtained in the preceding step into a polymer network. Further, the present invention relates to the manufactured polymer network and to a composite material comprising the polymer network. Furthermore, the present invention relates to adhesives and coating materials comprising said polymer network.

Description

METHOD FOR THE MANUFACTURE OF A SORBIC ACID-BASED POLYMER

NETWORK

The present invention relates to a method for the 5 manufacture of a polymer network. Further, the present invention relates to the manufactured polymer network and to a composite material comprising the polymer network. Furthermore, the present invention relates to adhesives and coating materials comprising said polymer network.

10 Green engineering, in particular the manufacture of biobased polymers and composites derived from plants or natural products is a rising industry. Green Engineering is the design, commercialization and use of processes and products that are feasible and economical while reducing pollution at 15 the source and minimizing the risk to human health and the environment. More particularly, green engineering focuses on bio-based material resources, availability, sustainability, bio-based polymer formation, extraction and refining technologies, and the need for integrated research in areas 20 such as adhesives, resins, plastics, and composites derived from plant oils, proteins, starches, and natural fibers in terms of structures, properties, manufacturing, and product performance .

US 4,074,008 describes epoxy resins polymerizing on exposure 25 to actinic radiation having at least two photopolymerizable groups and at least two 1,2-epoxide groups per molecule in the presence of aromatics, ketone, alcohol, or ether based solvents. Further, in US 4,074,008, the used materials are photopolymerized and the remaining epoxide groups are 30 subsequently cross-linked with a curing agent such as an aromatic amine or polythiol at a temperature of 100-200 °C. US 3,936,366 describes compounds having at least three 3-sorboyloxy-2-hydroxypropyl groups directly attached to ether 2 oxygen atoms and polymerized by exposure to actinic radiation in the presence of a sensitizer. Specifically, these compounds may be obtained by the reaction in organic solvents of sorbic acid with a substance having at least 5 three glycidyl ether groups or of glycidyl sorbate with a substance having at least three phenolic or alcoholic hydroxyl groups. More specifically, the sorbic acid is reacted with epoxy groups. The resulting ester is subjected to actinic radiation to result in polymerization. The cross-10 linking itself is achieved by the reaction of 1,2-epoxide groups with a heat-curing agent.

US 5,830,952 describes a polymer prepared from the reaction in an organic solvent of: - a compound having about two epoxy groups; with 15 - a linking compound having conjugated carbon-carbon double bonds or a carbon-carbon triple bond as well as a moiety capable of reacting with an epoxy group. An example is sorbic acid; with - acrylic monomers to render the polymers water dispersible 20 The polymerized acrylic portion is covalently linked with the polymer by previously mentioned linking compound. Further, in US 5,830,952 describes a compound having conjugated carbon-carbon double bonds, in which acrylic monomers are involved which copolymerize with the linking 25 compound to form a copolymer.

The polymers of US 4,074,008, the compounds of US 3,936,366 and the polymers of US 5,830,962 present the drawback of being difficult to handle and/or difficult to further process. A further drawback is the use of organic solvents. 30 Organic solvents have the inconveniency of being environmentally unfriendly and/or having a boiling point preventing their complete elimination at the end of the reaction.

3

Additionally, in the methods described in prior art, a further drawback is that sorbic acid (SA) monomers are unpredictable when polymerizing to a polymer network, in particular in ethyl sorbate (ESA) and ESA mixtures of other 5 SA based resins.

Accordingly, there is a need to provide, at an industrial level, polymer networks derived from natural sources, also designated as bio-based polymer networks. Specifically, there is a need for providing stable polymer 10 networks from natural sources in order to be used in industrial processes for the fabrication of adhesives, resins, plastics, and composites. Further, there is a need to provide sorbic acid-based polymer networks that do not present the above-mentioned drawbacks of the prior art.

15 The goal of the present invention, amongst other goals, is to provide a polymer network fulfilling the requirements of green engineering, such as reducing the generation of pollution at the source and minimizing the risk to human health and the environment, as well as providing a method 20 that does not present the drawbacks of the prior art. More specifically, this goal is achieved by the method for the manufacture of a sorbic acid-based polymer network comprising: a) reacting a glycidylether with one or more 25 compounds comprising a sorbic acid-based moiety and obtaining a product having a pre-determined viscosity; and c) polymerizing the product obtained in the preceding step into a polymer network.

30 Surprisingly, it has also been observed in the present invention that in polymer network formation during curing of ester monomers based on sorbic acid, several monomers containing a sorbic acid-based ester do not cure (remain 4 liquid) whereas others give a rubber or even solid thermoset material.

In the method of the present invention, the glycidylether reacts with one or more compounds comprising a 5 sorbic acid-based moiety, such as one compound, two or more compounds, three or more compounds, four or more compounds, five or more compounds, six or more compounds. The amount of compounds reacting with the glycidylether depend the amount of glycidyl unit present in the glycidylether. For example, 10 when the glycidylether is a diglycidylether, one compound comprising a sorbic acid-based moiety or two compounds comprising a sorbic acid-based moiety can react with the diglycidylether.

A glycidylether is a compound comprising an ether 15 functional group -0- and a cyclic ether unit, also designated as an oxirane unit. A monoglycidylether is represented in formula (1) and a diglycidylether is represented in formula (2).

0 (1) 20 O 0(2) R represents an alkyl chain, a cycloalkyl or an aryl. R can be substituted or unsubstituted.

In the context of the present invention, the compound 25 comprising a sorbic acid-based moiety can be sorbic acid, or a derivate of sorbic acid, such as sorboyl chloride (also designated as sorbic acid chloride).

Sorbic acid, (also designated as 2,4-hexadienoic acid and abbreviated as SA), is a natural organic compound used 5 as a food preservative. It has the chemical formula C6H802. Sorbic acid is represented in formula (3).

O

(3) 5 A sorboyl halide comprises a -(C=0)-X functional group and can also be designated as a halide of 2,4-hexadienoyl. The halide X can be any halogen (X = F, Cl, Br, I, At). Advantageously the sorboyl halide is sorboyl chloride.

10 Sorbic chloride can also be designated as 2,4-hexadienoyl chloride, sorbic acid chloride, or sorboyl chloride.

The compounds comprising a sorbic acid-based moiety can advantageously comprise further one or more alcohol functions (-0H) that can react with the glycidylether in 15 step a) .

The compound comprising the sorbic acid-based moiety according to the present invention can also comprise substitutions on said moiety, such as alkyl rests, advantageously a C1-C6 alkyl, such as a methyl, ethyl, 20 propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, n-hexyl. The sorbic acid-based moiety according to the present invention can also be substituted by one or more alcohol functions (also designated by hydroxyl, -OH) or by one or more carboxylic acid functions (-COOH). Muconic acid 25 is an example of a compound comprising a sorbic acid moiety substituted with a carboxylic acid group. The sorbic acid-based moiety comprises two double carbon bonds that are conjugated. Accordingly, it can also be designated as a conjugated diene moiety. The compound comprising the 30 conjugated diene moiety can also be muconic acid.

6

The reaction products of a glycidylether and the one or more compounds comprising a sorbic acid-based moiety depend on the ratio of both reactants. This reaction results in the formation of a hydroxy-ester. The resulting products 5 (hydroxy-ester) can represented as indicated in formulas (4) to (9):

O

-R

OH (4)

-R

0 (5)

O

-R-o 10 OH O (6) HO^^^I^^^O-R- 0 (7) o o OH OH (8)

H0‘/”^>VSvyX,,^^0-R-^ H

° 0 (9) 7

In the reaction carried out in step a), the ratio (equivalents) of glycidylether to the compound comprising a sorbic acid-based moiety can be 1:1-2. Said ratio can take any values in that range, such as 1:1.1, 1:1.2, 1:1.3, 5 1:1.4, 1:1.5, 1:1.6, 1:1.7, 1:1.8, 1:1.8, 1:1.9, 1:2. In the above formulae, examples are gives in which the one or more compounds comprising a sorbic acid-based moiety is sorbic acid. In formulae (4) and (5), a monoglycidyl ether (1) reacts with one sorbic acid. In formulae (6) and (7), a 10 diglycidylether (2) reacts with one sorbic acid, in formulae (8) and (9), a diglycidylether (2) reacts with two sorbic acids. According to the present invention, a polyglycidylether (comprising 3 or more glycidylether units) can react with more than two sorbic acid molecules.

15 In formulas (4) to (9), R represents a linear alkyl, a cycloalkyl or an aryl. Advantageously, the linear alkyl is a C1-C12 alkyl. More advantageously, R is chosen from the group comprising methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, and n-hexyl. The linear 20 alkyl can be unsubstituted or substituted by an alkyl, an aryl, a functional group chosen from the group alcohol (-OH) , ketone (-CO-), halogen, a thiol (-SH) . Advantageously, the cycloalkyl is chosen from the group cyclohexyl, cycloheptyl, cyclooctyl. The cycloalkyl may or may not be 25 substituted by an alkyl, an aryl, a functional group chosen from the group alcohol (-OH), ketone (-CO-), halogen, a thiol (-SH). Advantageously, the aryl is chosen from the group a phenyl, a benzyl, a naphtyl. The aryl may or may not be substituted by an alkyl, an aryl, a functional group 30 chosen from the group alcohol (-OH), ketone (-CO-), halogen, a thiol (-SH).

In step a), the glycidylether and the one or more compounds comprising a sorbic acid-based moiety react 8 together and can subsequently polymerize. The products obtained in the method of the present invention can also be designated as a resin. The resin materials obtained in step a) have reactive conjugated carbon-carbon double bond so 5 that curing via a free radical polymerization process is possible. Free radicals are obtained in order to carry out the polymerization, via thermal or UV initiation using suitable peroxides. In the present invention, the resins obtained after step a) can either be stabilized with a 10 suitable inhibitor or be polymerized (without initiators and inhibitors) under suitable conditions like: elevated temperature, exposure to atmospheric air or exposure to UV irradiation. When the conjugated double bond or any double bond is absent, no polymerization can occur via free radical 15 mechanism.

In the method of the present invention, step c) is a polymerization step, namely a cross-linking step. The cross-linking is achieved by free radical polymerization. Accordingly, step c) is advantageously a free radical 20 polymerization. The free radical polymerization comprises an initiation step, a propagation step and a termination step. In the method of the present invention, cross-linked polymers are obtained after step c). In the present invention, the sorbic acid-based moiety only is responsible 25 for the cross-linking. Accordingly, in the method of the present invention, the cross-linking is not achieved by a polycarboxylic acid anhydride or a heat curing agent. The method of the present invention provides a polymer network that is easier to handle and for this reason, the polymer 30 network obtainable by the method according to the present invention also provides the possibility of modifying its physical properties with the presence of additives, for 9 example, is applicable for all aspects and embodiments of the present invention.

Accordingly, surprisingly in the specific resin compositions obtained by the method of the present 5 invention, the sorbic acid moiety is polymerized to result in a cross-linked network.

The above goals and aims are achieved as well, by the method according to the present invention comprising after step a) and before step c): 10 b) reacting the product obtained in step a) with an acid anhydride or an acyl halide.

According to this embodiment of the present invention, the method for the manufacture of a sorbic acid-based polymer network can be described as comprising: 15 a) reacting a glycidylether with one or more compounds comprising a sorbic acid-based moiety and obtaining a product having a pre-determined viscosity; b) reacting the product obtained in step a) with 20 an acid anhydride or an acyl halide; and c) polymerizing the product obtained in the preceding step into a polymer network.

In the context of the present invention, the acid anhydride is an organic compound that has two acyl groups 25 bound to the same oxygen atom. Most commonly, the acyl groups are derived from the same carboxylic acid, the formula of the anhydride being (R'C(0))20, wherein R'can be an alkyl or an alkenyl. Specifically, R' may be, for example, an alkyl group of any length, but preferably an 30 alkyl group comprising at most 6 carbon atoms, more preferably at most 4 carbon atoms, even more preferably at most 3 carbon atoms, most preferably at most 2 carbon atoms. Alternatively, R' can also be an alkenyl comprising at least 10 one carbon-carbon double bond, such as one, two or three carbon-carbon double bond. Symmetrical acid anhydrides of this type are named by replacing the word acid in the name of the parent carboxylic acid by the word anhydride. Thus, 5 (CH3CO)20 is called acetic anhydride. Symmetrical, mixed (or unsymmetrical) acid anhydrides, or cyclic anhydride are examples of the anhydrides used in step b). In the present invention, the acid anhydride is preferably selected from the group propionic anhydride, acetic anhydride, formic 10 anhydride, acrylic anhydride, methacrylic anhydride, cinnamic anhydride.

The cyclic anhydrides are preferably selected from the group maleic anhydride, phthalic anhydride, itaconic anhydride, citraconic anhydride, succinic anhydride.

15 In the context of the present invention, an acyl halide (also known as an acid halide) is a chemical compound containing a -COX functional group, which consists of a carbonyl group singly bonded to a halogen atom (X). The general formula for such an acyl halide can be written 20 R'COX, where R' may be, for example, an alkyl group of any length, but preferably an alkyl group comprising at most 6 carbon atoms, more preferably at most 4 carbon atoms, even more preferably at most 3 carbon atoms, most preferably at most 2 carbon atoms. Alternatively, R' can also be an 25 alkenyl comprising at least one carbon-carbon double bond, such as one, two or three carbon-carbon double bond. CO is the carbonyl group, and X represents the halide, such as chloride. Acyl chlorides are accordingly advantageously used in the method according to the present invention. More 30 advantageously, the acyl chloride is chosen from the group acryloyl chloride, methacryloyl chloride, acetyl chloride.

The effect of step b) is predominantly to reduce the viscosity of the product and/or additionally to increase the 11 number of reactive functional groups to increase the crosslink density of the polymer network.

The viscosity is advantageously controlled before or during any of the steps of the present invention.

5 Advantageously, the viscosity is controlled during step a) and/or step b) and before step c). The viscosity of the resins obtained by the method according to the present invention is regulated by: - varying the ratio of glycidylether to compound comprising 10 a sorbic acid-based moiety (step a)); and/or - by modification of the product (resin) by reaction with an acid anhydride or an acyl halide (step b)); and/ or - by the use of an additive, such as a reactive diluents, before carrying out step c)(i.e. during or after step a), 15 during or after step b)).

Accordingly, in the context of the present invention, a predetermined viscosity is a viscosity that is suitable to carry out step a) and/or step b) and/or step c) until the desired level of reaction is reached. Specifically in step 20 c), a (cross-linking) polymerization step is carried out in which the product obtained in the preceding step is polymerized. Advantageously, a further step carried out before step c) can be carried out to control the viscosity of the resin to be a liquid prior to carry out step c. The 25 viscosity of the product obtained in the steps preceding step c) is in a liquid form at the moment of polymerization in step c).

In the context of this embodiment, when step b) is carried out, no polymerization occurs in step a).

30 In the context of the present invention, the method steps are preferably performed without using additional solvents. Solvents are often not bio-based. If a solvent is used, it is recommended to use a bio-based solvent. The 12 synthesis methods are chosen in such a way that the resin materials can be prepared in one reactor (single-pot reactions). The method according to the present invention provides products with high yields so that additional 5 purification steps are not necessary.

According to the present invention, step a) and b) are carried out at a temperature suitable to carry out the reactions as well as providing a reaction mixture that has a controlled viscosity.

10 Advantageously, step a) of the method according to the present invention is carried out at a temperature below 100°C.

Advantageously, step b) of the method according to the present invention is carried out at a temperature in the 15 range 10°C to 60°C. Step b) can also be carried out at higher temperature than 60°C (i.e. 80°C-90°C) if the catalyst used in step b) allows it, or if no catalyst is used. Step b) can also be carried out at a temperature between 0°C and 20°C, if the reactivity of the reaction carried out in step b) is 20 exothermic (i.e. with acyl halides, reactions are performed at 0°C at first and when the acyl halide is added, the reaction is carried out at room temperature). The temperature of the reaction carried out in step b) is advantageously so that the viscosity of the products is 25 sufficiently low to provide a good mixing in the machinery or apparatus in which the method of the present invention is carried out.

Accordingly, in the present invention, step a) and/or b) of the method comprise a step wherein the viscosity is 30 controlled. Step b) has the effect of controlling, or if necessary decreasing, the viscosity of the resin obtained in step a) 13

In the context of the present invention, the viscosity of the reaction products is sufficiently low so that moulds or reactors can be easily filled prior to the curing process. In addition, reinforcing materials such as glass 5 fiber mats can be easily impregnated with the resin after step a) or step b) .

According to the present invention, step a) is carried out at a temperature of at most 100°C at the moment of mixing the reactant participating in the reaction of step a).

10 Advantageously, the temperature is at most 91°C, more advantageously the temperature is in the range 85-91°C. The temperature can also be raised of about 2-10% (preferably 5-8%) of the reaction temperature, at the end of step a), i.e. once the glycidylether and the sorbic acid-based moiety have 15 reacted.

According to the present invention, step b) is carried out at a temperature in the range 10 to 60°C, preferably 20 to 50°C. Advantageously, step b) is carried out at a temperature of at least 10°C, more advantageously at least 20 20°C, even more advantageously at least 30°C, most advantageously at least 40°C. Preferably, step b) is carried out at a temperature of at most 60°C, more preferably a temperature of at most 50°C. Advantageously, step b) is carried out at room temperature.

25 Advantageously, in of the method according to the present invention, the polymerization is step c), that is a free radical polymerization (i.e. curing) can be done thermally (addition of thermally decomposable initiators) or by UV-irradiation (addition of photo initiators).

30 According to the present invention, step c) is carried out at a temperature of at most 150°C, preferably at most at 140°C. Advantageously, the temperature is in the range 10 to 150°C, 10 to 140°C, 10 to 100°C, more advantageously in the 14 range 10 to 90°C. Preferably, the polymerization is carried out at a temperature of at least 10°C, more advantageously at least 20 C. The polymerization can be preferably carried out at room temperature, i.e. at atmospheric pressure at 5 temperatures in the range in the range 20 to 150°C or in the range 20 to 140°C. Step c) can also be carried out at higher temperatures, provided no degradation of the products occurs. Accordingly, step c) is a curing step, advantageously, the curing temperature is at room 10 temperature. Advantageously, the curing is carried out at a first temperature during a pre-determined period of time and the temperature is then increased (post-curing).

According to another aspect of the method of the present invention, step b) and step c) may be carried out at 15 the same temperature.

Advantageously in the present invention, in steps a) and/or c), no additional solvent is required in the method. This is to be understood that no removal of excess solvent is needed at any steps of the method according to the 20 present invention. A further advantage is that no solvent that is toxic for the environment is involved in step a) and/or step c) of the method according to the present invention. Furthermore, no difficult separation of the solvent from the final products is necessary.

25 Advantageously, the polymerization in step c) is carried out in the presence of an initiator. The polymerization initiator can be selected from the conventional initiators for free-radical polymerization.

They include in particular organic peroxy compounds, such as 30 peroxides, peroxycarbonates and peresters. Combinations of peroxy compounds can also be used. Typical examples of the suitable peroxy initiators are C6-C2o acyl peroxides such as decanoyl peroxide, benzoyl peroxide, octanoyl peroxide, 15 stearyl peroxide, 3,5,5-trimethyl hexanoyl peroxide, per-esters of C2-C18 acids and C1-C5 alkyl groups, such as t-butylperbenzoate, t-butylperacetate, t-butyl-perpivalate, t-butylperisobutyrate and t-butyl-peroxylaurate, and 5 hydroperoxides and dihydrocarbyl (C3-C10) peroxides, such as diisopropylbenzene hydroperoxide, di-t-butyl peroxide, cumyl hydroperoxide, dicumyl peroxide or combinations thereof.

Radical initiators different from peroxy compounds are not excluded. A suitable example of such a compound is a,a'~ 10 azobisisobutyronitrile. The amount of radical initiator is suitably from 0.01 to 3% wt, based on the weight of the product obtained after steps a) or b). Further, an accelerator may be added. Examples are cobalt naphthenate, cobalt octoate, cobalt acetate, cobalt neodecanoate, 15 cobalt(II) 2-ethylhexanoate. Typical concentrations are 5-100 ppm (0.0005-0.01 wt% based on the weight of resin), although higher Co-concentrations are not excluded.

A reactive diluent can also be added before step c) of 20 the present method. Accordingly, in the method according to the present invention, a reactive diluent can be added to the product obtained in step a) or in step b) , before carrying out step c). Reactive diluents are monomers with low viscosity which have at least one reactive vinyl group 25 and form homogeneous mixtures with the previously described bio-based resins obtained after steps a) and b). Examples of reactive diluents are methyl methacrylate, styrene, methyl acrylate. The reactive diluents are advantageously biobased. Examples of bio-based reactive diluents are myrcene 30 (tested), limonene, pinene (alpha, beta). Other additives can also be used, such as chain transfer agents, dyes, fillers, flame retarding compounds, nucleating agents. Other (partly) bio-based materials containing reactive vinyl 16 groups can be added as well. An example is commercially available acrylated soybean oil.

Another aspect of the present invention relates to the sorbic acid-based polymer network obtainable by the method 5 according to the present invention. All the definitions, advantages and preferences described above for the method according to the present invention are applicable to all the aspects of the present invention.

Yet another aspect of the present invention relates to 10 a composite polymer material comprising the sorbic acid-based polymer network according to the present invention. Specifically, the sorbic acid-based polymer network manufactured according to the method of the present invention can be part of a coating composition and/or 15 composite polymer material such as glass fiber, wood flour, cork, stone, sand, basalt, flax and jute, quartz. Further, the sorbic acid-based polymer network according to the present invention can be used for its binding properties, alone or in a composition such as in glues, e.g. for glues 20 between metals, glass, wood based materials or plastics.

Accordingly, another aspect of the present invention relates to the sorbic acid-based polymer network material is used in adhesives or in coating materials. Adhesives are materials that fix items together. Adhesives cure (harden) 25 by either evaporating a solvent or by chemical reactions that occur between two or more constituents. Adhesives are advantageous for joining thin or dissimilar materials, as well as in applications where a vibration-damping joint is needed. Coating materials are covering materials that are 30 applied to the surface of an object, usually referred to as the substrate. In many cases coatings are applied to improve surface properties of the substrate, such as appearance, adhesion, wettability, corrosion resistance, wear 17 resistance, and scratch resistance. In other cases, in particular in printing processes and semiconductor device fabrication (where the substrate is a wafer), the coating forms an essential part of the finished product.

5 Still another aspect of the present invention relates to the compounds manufactured in step a) of the method according to the present invention.

Yet another aspect of the present invention relates to the compounds manufactured after carrying out the two first 10 steps of the method of the present invention, steps a) and b). Accordingly, the compounds obtainable after step b) of the method according to the present invention are diesters and a schematic representation is given in formulae (I) to (X). As described above, R' is given by the acid anhydride 15 or acyl halide reacted in step b) represented by the formulae (A) and (B), respectively.

O O

R' ^ ^ R' (A) 0 R'^^X (B) 20 wherein R’ is an alkyl, or an alkenyl having one or more carbon-carbon double bond, preferably comprising at most six carbon atoms, more preferably comprising at most four carbon atoms, even more preferably comprising at most three carbon atoms, most preferably comprising at most two 25 carbon atoms. In these compounds obtainable by the method of the present invention comprising step a) and b), R' is preferably a short alkyl chain: CH3 or CH2CH3 such as when step b) is carried out with formic anhydride, or acetic anhydride. In the context of the present invention, a 18 carbon-carbon double bond can also be designated by an unsaturated carbon-carbon bond.

When step b) is carried out with compounds (4) and (A) or (B), the resulting product has the formula: 5

O

0 (I)

When step b) is carried out with compounds (5) and (A) or (B) , the resulting product has the formula:

O

R1 -R

0 (II) 10 When step b) is carried out with compounds (6) and (A), the resulting product has the formula: o ° R,^0 0 O (Ilia)

When step b) is carried out with compounds (6) and (B) , the resulting products have the formulae: 15 19 o -R-

R'\^° X

o (Illb)

O

R^>f^0 °Ns^-RI

0 o (IIIc)

When step b) is carried out with compounds (7) and (A), the resulting product has the formula: o o 5 0 O (IVa)

When step b) is carried out with compounds (7) and (B), the resulting products have the formulae: 0 0

R -R-0^^Ss'y^^^0^^'R

O (IVb) o

R' //^0///Νγ/Νχ0-R-0////^SV//NxX

0 o (IVc) 20

When step b) is carried out with compounds (8) and (A) or (B), the resulting product has the formula: o o R'\^° γ ο ο (V)

When step b) is carried out with compounds (9) and (A) 5 or (B), the resulting product has the formula: o o R' ^ -R O' *""" '' 'O' 'R'

~y ^ (YD

Accordingly, this aspect of the present invention relates to compounds comprising two ester (-C00-) groups 10 (diesters), three ester groups (triesters), four esters groups (tetraesters). In the compounds (I) to (VI) described above, R represents a linear alkyl, a cycloalkyl or an aryl (as defined above for compounds (4) to (9) and R' represents preferably an alkyl, or alternatively an alkenyl comprising 15 at least one carbon-carbon double bond.

In the context of the present invention, "at least one" is to be understood as one, two, three, four, five, six. "At least one" can also to be understood as at least two, at least three, at least four, at least five, at least six, or 20 more.

In the context of the present invention, all the compounds described here above are terpene-based compounds. Said compounds are intermediary compounds of the method of the present invention. They are obtainable by step a) and 25 additionally step b) of the method according to the present invention .

5 21

The present invention is further described, without being limited to, by the figures and examples hereafter.

22

Figures

Figure la. 1H-NMR spectrum of pure BGE in CDCI3.

Figure lb. 1H-NMR spectrum of BGESA in CDCI3.

Figure 2a. 1H-NMR spectrum of pure GDGE in CDCI3.

5 Figure 2b. 1H-NMR spectrum of GDGESA1_1.5 in CDCI3.

Figure 3a. 1H-NMR spectrum of pure RDGE in CDCI3.

Figure 3b. 1H-NMR spectrum of RDGESA1_1.75 in CDCI3.

Figure 4a. Stress-strain curve during compression of cured GDGESA1_1.55 resin : 0 weeks in water.

10 Figure 4b. Stress-strain curve during compression of cured GDGESA1_1.55 resin: 4 weeks in water.

Figure 4c. Stress-strain curve during compression of GDGESA1_1.65/myrcene = 85/15: 0 weeks in water .

15 Figure 4d. Stress-strain curve during compression of GDGESA1_1.65/myrcene = 85/15: 4 weeks in water .

Figure 5a. Influence of water on the compressive yield strength: cylinders made of cured GDGESA1_1.55 20 resin.

Figure 5b. Influence of water on the compressive modulus: cylinders made of cured GDGESA1_1.55 resin.

25 30 23

Examples

One of the aims was to show if polymerization (curing) can occur when a compound contains a single SA moiety or that two or more SA moieties are needed in one molecule. Note 5 that an epoxy group can react from two sides and thus two isomer products (with either a primary or a secondary hydroxyl group) may result. The chemical structure of the isomer with the secondary hydroxyl group isomer has been drawn for each model compound. It is not always clearly to 10 observe in the 1H-NMR spectra which isomer has been formed.

Example 1; Benzyl glycidyl ether with SA (BGE/BGESA)

Benzyl glycidyl ether (BGE) has only one epoxy group and 15 hence can only form a BGESA mono-ester. The chemical structures of BGE and BGESA are schematically depicted in table 1. The preparation of BGE with SA was carried out according to the present invention. The 1H-NMR spectra of both BGE and BGESA are shown in figure la and lb, 20 respectively. Both protons (e) and (g) give two peaks. The position of protons (el,2) and (f) moves downfield to approximately 4.25 and 4.05 ppm, respectively. Some unreacted BGE can be observed from the presence of two peaks between 2.5-3 ppm (el,2 of BGE) and 3.75 ppm (gl,2 of 25 BGE). Peak (d) from the SA moiety gives a doublet with positions at 5.78 and 5.81 ppm.

24

Table 1. Starting material BGE and product BGESA

Ö*) 0*),^ (*) -* Starting material: JL o J-—-o BGE (benzyl glycidyl ether) n/ \/ (f*) (i*) (h*) (g*) ω (ij (i)^ ^>(i) / 0) (h/ o (g)< \ Product:

(f))-0H

.,/ BGESA mono-ester

(eK

O

0=\ \(d) (c)/ \(b) (a)/

5 Example 2: GDGESA: Glycerol diglycidyl ether GDGE with SA

Glycerol diglycidyl ether has an average of two epoxide groups per molecule. This may result in GDGESA mono-ester and GDGESA di-ester compounds which are schematically 10 represented in table 2. In practice, approximately 1.5 mole SA can react with 1 mole GDGE. Figures 2a and 2b show the 1H-NMR spectra of GDGE and GDGESA1_1.5, respectively. The shift of peaks (el,2) from 2.6/2.8 ppm to 4.25 ppm in the 1H-NMR spectrum of GDGESA1_1.5 shows the formation of an ester 25 bond. The obtained resin almost exclusively consists of GDESA di-ester since only a small amount of unreacted epoxide is left (see residual peaks denoted with (el,2*). Proton d that is part of the SA moiety only shows a large 5 doublet at 5.78/5.81 ppm. There are no traces present of free SA for which proton d* should give a doublet at 5.76/5.80 ppm.

Table 2. Starting material GDGE and product GDGESA

OH fc*) Starting material: J \GDGE (glycerol diglycidyl (g*) (g*) ether) (e*) / °\ (a)\ /(f*> \b) (8Λ (c)\ ? 7(d) r -c (fy—0H / ‘Λ )- 0=\ ° \ (d) (g)/

(c)^ (fD OH

\(b) (a\ ƒ

Product 1: //^ (c# GDGESA (mono-ester) \

Mb) (a)f

Product 2: GDGESA (di-ester 10 26

Example 3: RDGESA: Resorcinol diglycidyl ether RDGE with SA

Resorcinol diglycidyl ether has an average of two epoxide groups per molecule. After reaction with SA, RDGESA mono-5 ester and RDGESA di-ester can be obtained. The chemical structures of RDGE and RDGESA are shown in table 3. The 1H-NMR spectrum of RDGE and RDGESA1_1.75 are shown in figure 3a and 3b, respectively.

It can be seen that proton (d) corresponds to a doublet at 10 5.79/5.83 ppm which implies the formation of an ester bond since the doublet of peak d* of pure SA is located at 5.76/5.80 ppm. Almost all epoxide groups have reacted since there are almost no residual peaks left which correspond to the epoxide (el,2*).

15 27

Table 3. Starting material RDGE and product RDGESA.

5

ZX o ^ (f*) (e*) Starting material: RDGE

(e*) ^ W / (resorcinol diglycidyl (g*) (g*) o' ether) (e*) / °C (\ l 7 (f*) a \ / v(b) (g*)< / \ 3 1 iJ "y—oh (f)\-OH (g) (e) \ /0 )/(d} \ ,.// 0 C \ / \ (S)< -η)—

Product: P

°^=\ )/(dl RDGESA (mono-ester) // \(b) (a)<f

Product: RDGESA (di-ester) 28

Example 4: Recipes GDGESA1_1 (heating block) 5 9.04 g (0.044 moles) GDGE, 4.94 g (0.044 moles) SA, 153 mg TEBAC (1.5 mol% based on GDGE) and 8 mg hydroquinone (0.06 wt% based on weight GDGE + SA) were added to a 20 ml glass vial containing a stirring magnet. The vial was capped with a Teflon coated rubber and placed in a heating block at 85 10 °C. The stirring rate was 500 ppm. After 7 h, the reaction was stopped. A transparent brown/orange viscous liquid was obtained.

GDGESA1_1.55 (glass reactor) 15 106.5 g (0.95 moles) SA, 2.09 g TEBAC (1.5 mol% based on GDGE) and 114 mg hydroquinone (0.05 wt% based on weight GDGE + SA) were added to a 300 ml double wall glass reactor, equipped with motorized stirrer and nitrogen inlet. The reactor was heated to 80 °C whereas the powder mixture 20 (SA+TEBAC+hydroquinone) was homogenized by stirring at 230 rpm. After approximately 15 min stirring at 80 °C, 125.04 g (0.612 moles) GDGE was slowly added. The temperature was subsequently increased to 91 °C. At T = 91 °C, tR= 0. The reaction mixture became transparent after approximately tR = 25 1.5 h. The reaction was stopped after tR = 7 h. A transparent yellow viscous liquid (227.6 g yield) was obtained.

RDGESA1_1 (heating block) 8.99 g (0.040 moles) RDGE, 4.54 g (0.040 moles) SA, 138 mg 30 TEBAC (1.5 mol% based on RDGE) and 6 mg hydroquinone (0.06 wt% based on weight RDGE + SA) were added to a 20 ml glass vial containing a stirring magnet. The vial was capped with a Teflon coated rubber and placed in a heating block at 85 29 °C. The stirring rate was 500 ppm. After 7 h, the reaction was stopped. A transparent brown/orange wax was obtained.

RDGESA1_1.75 (heating block) 5 5.52 g (0.025 moles) RDGE, 4.88 g (0.044 moles) SA, 84 mg TEBAC (1.5 mol% based on RDGE) and 8 mg hydroquinone (0.06 wt% based on weight RDGE + SA) were added to a 20 ml glass vial containing a stirring magnet. The vial was capped with a Teflon coated rubber and placed in a heating block at 85 10 °C. The stirring rate was 500 ppm. After 7.5 h, the reaction was stopped. A transparent brown/orange wax was obtained.

Example 5: Polymerization reactions of compounds with SA moieties 15

Curing of GDGESA1_1.55 168.88 g GDGESA1_1.55 resin was mixed with 5.10 g MEKP solution (3 wt% based on total weight resin). The resin was 20 heated up to 70°C + 700 mbar for 15 min to decrease the viscosity and to remove entrapped air. The resin was subsequently poured into a mold containing 12 cylindrical holes (1 x b = 21 x 23 mm). The mold was placed in the oven at 90 °C which was continuously purged with a nitrogen flow. 25 After 5 h a vacuum was applied. The mold was kept at 90 °C for approximately 16 h. The mold was then removed from the oven and allowed to cool to room temperature.

The curability of the previously described synthesized 30 resins containing SA moieties (see Example 1-4) was tested. MEKP (30-35 wt% methyl ethyl ketone peroxide solution) was used as the free radical initiator. The resins were not purified prior to the polymerization reaction. The SA mono- 30 ester resins having only one SA moiety are summarized in table 4a. The resins obtained from diglycidyl ether compounds are summarized in table 4b. These resins consist of both SA mono-ester and SA di-ester, depending on the 5 selected initial ratio SA/glycidyl ether prior to synthesizing the resin. The fraction of SA di-ester in the resin can be enlarged by increasing the SA/glycidylether ratio .

The abbreviation RT stands for room temperature.

10

Table 4a. Curing results of resins only containing SA monoesters

Description resin at Curing conditions Product description after physical state at RT curing treatment

Ethyl sorbate* 3 wt% MEKP Liquid at 90 °C

Low viscous liquid 90 °C + 800 mbar 6 h Liquid at RT

BGESA 3 wt% MEKP Liquid at 90 °C

Low viscous liquid 90 °C + 800 mbar 6 h Liquid at RT

BGESA / Ethyl sorbate 3 wt% MEKP

50 / 50 molar ratio 90 °C + 800 mbar 6 h Liquid at 90 C

Low viscous liquid Liquid at RT

ethyl sorbate: commercially available sample used here as comparative sample 15 ** oven is flushed with N2 prior to curing.

From table 4a, it can be observed that the tested SA monoesters do not sufficiently cross-link to result in a solid material.

20 31

Table 4b. Curing results of resins containing mixtures of SA mono-esters and SA di-esters

Description resin at Curing conditions** Product description physical state at RT after curing and cooled

to RT

GDGESA1_1 3 wt% MEKP Solid, rubber material

Viscous liquid 90 °C + N2 4.5 h 90 °C + vacuum 48 h GDGESA1_1.5 3 wt% MEKP Solid, glassy material

Viscous liquid 90 °C + N2 6.5 h 90 °C + vacuum 48 h RDGESA1_1 3 wt% MEKP Solid, rubber material

Solid (liquid at 90 °C) 90 °C + N2 4.5 h

90 °C + vacuum 48 h RDGESA1_1.75 3 wt% MEKP

Solid (liquid at 90 °C) 90 °C + N2 6.5 h Solid, glassy material 90 °C + vacuum 48 h 5 oven is flushed with N2 prior to curing.

The resins shown in table 4b consist of SA mono-esters and SA di-esters. It can be seen that these resins result in solid materials. Increasing the SA/epoxy ratio of the 10 mixture prior to the ring opening reaction results in an increased fraction of SA di-esters in the final resin. Consequently, the cross-link density of the cured resins will increase which transforms the cured material from rubber like into a glassy state at room temperature.

15

Thermal analysis

The Tg of the resins before and after curing was measured by DSC. The results are summarized in table 5.

20 32

Table 5. Tg of after curing

Composition Before curing, After curing,

Determined via DSC determined via DMTA Tg [°C] Tg [°C] GDGESA1_1 nTd n7Ö GDGESA1_1.5 nTd 81 RDGESA1_1 nTd nTd RDGESA1_1.75 nTd 106 N/D not determined 5 Viscosity measurements

Viscosity measurements of the polymer network obtained by the method of the present invention have a suitable viscosity for further treatment or handling.

10 Mechanical properties: Tensile tests cured GDGESA resins

Table 6. Results from tensile tests using dumbbell shaped bars .

GDGESA1_1.55 E modulus Maximum tensile

Sample no. [GPa] strength and tensile strength at break* [MPa] 1 Π7 50 (50) ~~2 ΓΓ8 53 (53) 1 ΓΤ8 54 (52) GDGESA1_1.55_myrcene=90/10 E modulus Maximum tensile

Sample no. [GPa] strength and tensile strength at break* [MPa] ~1 175 43 (43) * Values for tensile strength at break are listed between () 33

Compression tests cured GDGESA resins

Table 7 shows the curing conditions for GDGES1_1.55 (Bl) 5 which were used for preparation of test cylinders for compression tests.

Table 7. Composition and curing conditions used for compression tests.

Batch information Initiator Curing conditions GDGESA1_1.55 3 wt% 90 °C + N2 5 h MEKP 90 °C + 0 mbar 16 h 85 wt% GDGESA1_1.65 3 wt% 9 0 °C + 8 00 mbar 5 h + 15 wt% myrcene MEKP 90 °C + 0 mbar 48 h 100 °C + 0 mbar 8 h 10

Figures 4a-b and 4c-d show the compressive stress-strain curves of the in table 7 mentioned GDGESA samples after 0 weeks and 4 weeks storage in water, respectively. All GDGESA samples show ductile behavior. The stress increases after 15 reaching the yield stress. The cylinders eventually break with a loud bang. Addition of 15 wt% myrcene lowers the yield strength significantly (figure 4c-d). The storage of the GDGESA samples in water results in an increase of the maximum compressive strength as can be seen from figures 4a-20 d.

Figures 5a and 5b show the compressive yield strength and modulus, respectively as a function of storage time in water for GDGESA1_1.55. From figure 5a, it can be seen that the 25 presence of water reduces the compressive yield strength from around 80 to 60-65 MPa. Also the compressive modulus decreases due to the presence of water as can be observed 34 from figure 5b. Both decrease of compressive yield strength and modules tend to stabilize after 8 weeks in water. More tests are needed to see if stabilization occurs after 8 weeks .

5

Several GDGESA1_1.55 samples were stored in a saturated NaCl solution for 4 weeks. The results are shown in table 9. The compressive yield strength and modulus slightly decrease compared with the samples which were not stored in NaCl 10 solution. This was also observed when GDGESA1_1.55 cylinders were stored in distilled water. In addition, the maximum compressive strength increases when stored in NaCl solution.

Table 9. Compression tests on GDGESA1_1.55 samples stored in 15 a saturated NaCl solution.

Sample Storage Compressive Compressive Compressive time yield strength at modulus strength break [MPa] [GPa] [MPa] GDGESA1_1.55 0 weeks 82 123 ΓΤ3 + 3 wt% MEKP 77 114 1.3 cured at 90 81 125 1.4 °C (see 4 weeks 75 144 1.1 table 7) 74 146 1.1 76 148 1.2

Claims

A method for providing a sorbic acid-based polymer network comprising: a) reacting a glycidyl ether with one or more compounds comprising a sorbic acid-based group and obtaining a product that has a predetermined viscosity; and c) the polymerization of the product obtained in the previous step in a polymer network.

2. Method according to claim 1, wherein step c) is a free radical polymerization.

3. Process according to claim 1 or 2, comprising after step a) and before step c): b) the reaction of the product obtained in step a) with a carboxylic acid anhydride or an acyl halide.

4. A method according to any of claims 1 to 3, wherein prior to the execution of step c) a reactive diluent is added to the products obtained in step a) and / or b).

5. O (IIIa) wherein R is a linear alkyl, a cycloalkyl or an aryl and R 'is an alkyl, or an alkenyl comprising at least one carbon-carbon double bond.

5. A method according to any one of claims 1 to 4, wherein the glycidyl ether is a monoglycidyl ether or a diglycidyl ether.

The method of any one of claims 1 to 5, wherein the glycidyl ether is a diglycidyl ether and the ratio of diglycidyl ether: compound comprising a sorbic acid based group is 1: 1-2.

The method of any one of claims 1 to 6, wherein the glycidyl ether is substituted with a linear alkyl, a cycloalkyl or an aryl.

8. A method according to claim 7, wherein the alkyl or aryl is substituted with a group selected from a linear alkyl, a cycloalkyl, an aryl, a hydroxyl, a thiol and a halogen.

9. A method according to any one of claims 1 to 8, wherein the glycidyl ether is selected from the group consisting of benzyl glycidyl ether, cyclohexanedimethanol diglycidyl ether, glycerol diglycidyl ether, butanediol digigcidyl ether, and resorcinol diglycidyl ether.

The method according to any of claims 1 to 9, wherein step a) is carried out at a temperature of at most 100 ° C.

11. A method according to any one of claims 3 to 10, wherein step b) is carried out at a temperature in the range of 10 to 60 ° C.

The method of any one of claims 1 to 11, wherein step c) is a free radical polymerization that is carried out at a temperature in the range of 10 to 150 ° C.

A sorbic acid-based polymer network obtainable by the method of any one of claims 1 to 12.

A composite polymeric material comprising the polymer network of claim 13.

15. O (IVc) wherein R is a linear alkyl, a cycloalkyl or an aryl and R 'is an alkyl, or an alkenyl comprising at least one carbon-carbon double bond.

An adhesive comprising the polymer network according to claim 13. 10

A coating material comprising the polymer network according to claim 13.

17. Compound of formula: O-R O (I) wherein R is a linear alkyl, a cycloalkyl or an aryl and R 'is an alkyl, or an alkenyl comprising at least one carbon-carbon double bond. 20

A compound of formula: O R '-R O (II) wherein R is a linear alkyl, a cycloalkyl or an aryl and R' is an alkyl, or an alkenyl comprising at least one carbon-carbon double bond.

19. Compound of formula: o c '-R θ' S ^ R "O ^^ R"

A compound of formula: o c 'X O (Illb) wherein R is a linear alkyl, a cycloalkyl or an aryl and R' is an alkyl, or an alkenyl comprising at least one carbon-carbon double bond. 15

A compound of formula: O 0 o (III c) wherein R is a linear alkyl, a cycloalkyl or an aryl and R 'is an alkyl, or an alkenyl comprising at least one carbon-carbon double bond.

22. A compound of formula: O 0 O (IVa) wherein R is a linear alkyl, a cycloalkyl or an aryl and R 'is an alkyl, or an alkenyl comprising at least one carbon-carbon double bond.

23. Compound of formula: OOR '' θ 'Y ^ O-R-O // NV / ^ SO / ^ S'R o (IVb) wherein R is a linear alkyl, a cycloalkyl or an aryl and R' is a alkyl, or an alkenyl comprising at least one carbon-carbon double bond.

24. A compound of the formula: O R '"-R-

25. A compound of the formula: oo RV i θ / Ρ oo (V) wherein R is a linear alkyl, a cycloalkyl or an aryl and R 'is an alkyl, or an alkenyl comprising at least one carbon-carbon double bond is.

26. Compound of formula: o o R '-R- ^ Ό ^ R'

O (VI) 10 wherein R is a linear alkyl, a cycloalkyl or an aryl and R 'is an alkyl, or an alkenyl comprising at least one carbon-carbon double bond.